Add ability to create an Outgoing Webhook with the PATCH HTTP method via the UI (#3604)

# What this PR does

Closes https://github.com/grafana/oncall/issues/3564

## TODO
- [ ] add e2e tests for creating Outgoing Webhooks

## Checklist

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

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Added
+
+- Add ability to create an Outgoing Webhook with the PATCH HTTP method via the UI by @joeyorlando ([#3604](https://github.com/grafana/oncall/pull/3604))
+
 ### Changed
 
 - Handle message to reply to not found in Telegram send log ([#3587](https://github.com/grafana/oncall/pull/3587))

grafana-plugin/src/containers/OutgoingWebhookForm/OutgoingWebhookForm.config.tsx

@@ -122,6 +122,10 @@ export function createForm(
               value: 'PUT',
               label: 'PUT',
             },
+            {
+              value: 'PATCH',
+              label: 'PATCH',
+            },
             {
               value: 'DELETE',
               label: 'DELETE',