fix(gitea): platform automerge only fully works on Gitea v1.24 and Forgejo v10

lib/modules/platform/gitea/index.ts

@@ -558,6 +558,7 @@ const platform: Platform = {
                 getMergeMethod(platformPrOptions?.automergeStrategy) ??
                 config.mergeMethod,
               merge_when_checks_succeed: true,
+              delete_branch_after_merge: true, // older Gitea / Forgejo versions will ignore this, so no version check needed
             });
 
             logger.debug(

lib/modules/platform/gitea/readme.md

@@ -32,6 +32,8 @@ If you use Gitea packages, add the `read:packages` scope.
 
 - **Adding reviewers to PRs not supported**: Gitea versions older than `v1.14.0` do not have the required API.
 - **`platformAutomerge` (`true` by default) for platform-native automerge not supported**: Gitea versions older than v1.17.0 do not have the required API.
+  ⚠️ This is only fully supported on Forgejo v10+ because only there branches are deleted after automerge.
+  Ensure to use another solution to automatically delete branches after platform automerge.
 - **Git upload filters**: If you're using a Gitea version older than `v1.16.0` then you must enable [clone filters](https://docs.gitea.io/en-us/clone-filters/).
 
 ## Features awaiting implementation

lib/modules/platform/gitea/types.ts

@@ -199,6 +199,7 @@ export interface PRUpdateParams {
 export interface PRMergeParams {
   Do: PRMergeMethod;
   merge_when_checks_succeed?: boolean;
+  delete_branch_after_merge?: boolean;
 }
 
 export type CommentCreateParams = CommentUpdateParams;