Automate release note generation (#4004)

# What this PR does

- Automate our release note creation using `.github/release.yml` (see
docs
[here](https://docs.github.com/en/repositories/releasing-projects-on-github/automatically-generated-release-notes#example-configurations)).
- Add a GitHub Actions check for PRs to ensure that each PR contains one
`release:` label (which dictates how it will show up in the release
notes)

In addition, created the required labels:
<img width="701" alt="Screenshot 2024-03-04 at 13 25 45"
src="https://github.com/grafana/oncall/assets/9406895/eab83658-dfe9-478e-90d1-7cd66d9fce5d">

Once these changes are adopted and merged to `main` we can also delete
the `pr:no changelog` label.

## Checklist

- [ ] Unit, integration, and e2e (if applicable) tests updated
- [ ] Documentation added (or `pr:no public docs` PR label added if not
required)
- [ ] `CHANGELOG.md` updated (or `pr:no changelog` PR label added if not
required)

.github/CODEOWNERS

@@ -1,10 +1,5 @@
 * @grafana/grafana-oncall-backend
-
-# don't tag @grafana/grafana-oncall-backend on changes to CHANGELOG.md
-CHANGELOG.md
-
 /grafana-plugin @grafana/grafana-oncall-frontend
-
 /docs @grafana/docs-gops
 
 # `make docs` procedure is owned by @jdbaldry of @grafana/docs-squad.

.github/pull_request_template.md

@@ -12,4 +12,5 @@ This ensures that the issue(s) are auto-closed once the PR has been merged.
 
 - [ ] Unit, integration, and e2e (if applicable) tests updated
 - [ ] Documentation added (or `pr:no public docs` PR label added if not required)
-- [ ] `CHANGELOG.md` updated (or `pr:no changelog` PR label added if not required)
+- [ ] Added the relevant release notes label (see labels prefixed w/ `release:`). These labels dictate how your PR will
+    show up in the autogenerated release notes.

.github/release.yml

@@ -0,0 +1,14 @@
+changelog:
+  exclude:
+    labels:
+      - release:ignore
+  categories:
+    - title: Breaking Changes 🛠
+      labels:
+        - release:breaking-change
+    - title: Exciting New Features 🎉
+      labels:
+        - release:enhancement
+    - title: Other Changes
+      labels:
+        - release:patch

.github/workflows/verify-changelog-updated.yml

@@ -1,23 +0,0 @@
-name: Verify CHANGELOG updated
-
-"on":
-  pull_request:
-    types: [assigned, opened, synchronize, reopened, labeled, unlabeled]
-    branches:
-      - main
-      - dev
-
-jobs:
-  verfiy-changelog-updated:
-    name: Verify CHANGELOG updated
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v1
-      - name: Changelog check
-        uses: Zomzog/changelog-checker@v1.3.0
-        with:
-          fileName: CHANGELOG.md
-          noChangelogLabel: pr:no changelog
-          checkNotification: Simple
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/verify-release-label-added.yml

@@ -0,0 +1,23 @@
+name: Verify Release Label Added
+
+"on":
+  pull_request:
+    types:
+      - opened
+      - synchronize
+      - reopened
+      - labeled
+      - unlabeled
+    branches:
+      - dev
+
+jobs:
+  verfiy-release-label-added:
+    name: Verify Release Label Added
+    runs-on: ubuntu-latest
+    steps:
+      - uses: docker://agilepathway/pull-request-label-checker:latest
+        with:
+          prefix_mode: true
+          one_of: "release:"
+          repo_token: ${{ secrets.GITHUB_TOKEN }}

CHANGELOG.md

@@ -5,17 +5,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## Unreleased
-
-### Added
-
-- Add reset button to disable integration heartbeat @mderynck ([#3959](https://github.com/grafana/oncall/pull/3959))
-- Schedule deleted integration cleanup task to run every 12 hours @mderynck ([#3976](https://github.com/grafana/oncall/pull/3976))
-
-### Fixed
-
-- Fix selecting values in notification settings ([#9566](https://github.com/grafana/support-escalations/issues/9566))
-- Allow setting integration_filter to null in webhooks internal API ([#4011](https://github.com/grafana/oncall/pull/4011))
+*NOTE*: for all future release notes, please see the [Releases page](https://github.com/grafana/oncall/releases).
 
 ## v1.3.109 (2024-03-04)
 
@@ -1006,7 +996,7 @@ Minor bugfixes + dependency updates :)
 
 - Bring heartbeats back to UI by @maskin25 ([#2550](https://github.com/grafana/oncall/pull/2550))
 - Address issue when Grafana feature flags which were enabled via the `feature_flags.enabled` were only properly being
-  parsed, when they were space-delimited. This fix allows them to be _either_ space or comma-delimited.
+  parsed, when they were space-delimited. This fix allows them to be *either* space or comma-delimited.
   by @joeyorlando ([#2623](https://github.com/grafana/oncall/pull/2623))
 
 ## v1.3.16 (2023-07-21)
@@ -1188,7 +1178,7 @@ Minor bugfixes + dependency updates :)
 - Change OnCall plugin to use service accounts and api tokens for communicating with backend, by @mderynck ([#2385](https://github.com/grafana/oncall/pull/2385))
 - RabbitMQ Docker image upgraded from 3.7.19 to 3.12.0 in `docker-compose-developer.yml` and
   `docker-compose-mysql-rabbitmq.yml`. **Note**: if you use one of these config files for your deployment
-  you _may_ need to follow the RabbitMQ "upgrade steps" listed [here](https://rabbitmq.com/upgrade.html#rabbitmq-version-upgradability)
+  you *may* need to follow the RabbitMQ "upgrade steps" listed [here](https://rabbitmq.com/upgrade.html#rabbitmq-version-upgradability)
   by @joeyorlando ([#2359](https://github.com/grafana/oncall/pull/2359))
 
 ### Fixed