ci: update giteabot to v1.5.1, label conflict-free backports (#40247) (#40248)

Backport https://github.com/go-gitea/gitea/pull/40247

Release branch pushes run this branch's workflow.

_Written by Claude (Opus 5.5)._

.github/workflows/giteabot-backport.yml

@@ -4,13 +4,14 @@ on:
   push:
     branches:
       - main
+      - release/v*
   workflow_dispatch:
 
 permissions:
   contents: read
 
 concurrency:
-  group: ${{ github.workflow }}
+  group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: false
 
 jobs:
@@ -19,8 +20,8 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 30
     steps:
-      - uses: go-gitea/giteabot@b830f7aa810e43afc1b2f8e8968a30754e6ff5d3 # v1.4.1
+      - uses: go-gitea/giteabot@15b18fdedd98a80d0968d0bd9db3a9428814b808 # v1.5.1
         with:
           github_token: ${{ secrets.GITEABOT_TOKEN }}
           gitea_fork: giteabot/gitea
-          checks: backport
+          checks: backport,backport_conflict_free

.github/workflows/giteabot.yml

@@ -31,7 +31,7 @@ on:
       checks:
         description: Comma-separated list of non-backport checks to run
         required: false
-        default: backport_branches,labels,lock,feedback,last_call,milestones,lgtm,translation_comment,pr_actions
+        default: backport_branches,backport_conflict_free,labels,lock,feedback,last_call,milestones,lgtm,translation_comment,pr_actions
 
 permissions: {}
 
@@ -50,7 +50,7 @@ jobs:
       pull-requests: write
       statuses: write
     steps:
-      - uses: go-gitea/giteabot@b830f7aa810e43afc1b2f8e8968a30754e6ff5d3 # v1.4.1
+      - uses: go-gitea/giteabot@15b18fdedd98a80d0968d0bd9db3a9428814b808 # v1.5.1
         with:
           github_token: ${{ secrets.GITEABOT_TOKEN }}
-          checks: ${{ github.event.inputs.checks || 'backport_branches,labels,lock,feedback,last_call,milestones,lgtm,translation_comment,pr_actions' }}
+          checks: ${{ github.event.inputs.checks || 'backport_branches,backport_conflict_free,labels,lock,feedback,last_call,milestones,lgtm,translation_comment,pr_actions' }}

docs/release-management.md

@@ -24,6 +24,8 @@ Now, that's not a requirement anymore as our [backport bot](https://github.com/G
 
 The `backport/manual` label signifies either that you want to backport the change yourself, or that there were conflicts when backporting, thus you **must** do it yourself.
 
+The bot labels open PRs targeting `main` that have a `backport/<version>` label with `backport/conflict-free` when they would cherry-pick onto the latest release branch without conflicts.
+
 ### Format of backport PRs
 
 The title of backport PRs should be