feat: add cherry-pick command workflow and fix slash.yml

- Add cherry-pick-command.yaml using plumbing reusable workflow
- Enable /cherry-pick command in slash.yml configuration
- Fix repository name in slash.yml (was tektoncd/pipeline, now tektoncd/mcp-server)
- Update slash-command-dispatch action to v5.0.1
- Uses centralized cherry-pick logic from tektoncd/plumbing

Signed-off-by: Vincent Demeester <[email protected]>

Author: vdemeester

.github/workflows/cherry-pick-command.yaml

@@ -0,0 +1,32 @@
+# Cherry Pick Command Workflow
+#
+# This workflow is triggered by the /cherry-pick slash command from the slash.yml workflow.
+# It automatically cherry-picks merged PRs to the specified target branches.
+#
+# Usage: Comment `/cherry-pick <target-branch> [<target-branch> ...]` on a merged pull request
+# Example: `/cherry-pick release-v1.0.x`
+# Example: `/cherry-pick release-v1.0.x release-v1.1.x`
+#
+# Security Notes:
+# - Only users with "write" permission can trigger this command (enforced in slash.yml)
+# - Works safely with PRs from forks because it only cherry-picks already-merged commits
+# - Uses CHATOPS_TOKEN to create PRs and push to branches
+# - The action creates a new branch from the target branch, not from the fork
+
+name: Cherry Pick Command
+
+on:
+  repository_dispatch:
+    types: [cherry-pick-command]
+
+permissions:
+  contents: write
+  pull-requests: write
+  issues: write
+
+jobs:
+  cherry-pick:
+    name: Cherry Pick Actions
+    uses: tektoncd/plumbing/.github/workflows/_cherry-pick-command.yaml@4b57443b85569e5bb7d9ee440bf5cae99cb642cb
+    secrets:
+      CHATOPS_TOKEN: ${{ secrets.CHATOPS_TOKEN }}

.github/workflows/slash.yml

@@ -12,8 +12,8 @@
 # named <command>-command which must exist in the repository.
 #
 # Supported commands:
-# - /land: invokes the land-command workflow, to land (merge) PRs
-#          stacked through ghstack
+# - /retest: re-trigger workflows that failed on a given PR
+# - /cherry-pick <branch>: cherry-picks the merged PR to the specified branch
 #
 # When a command is recognised, the rocket and eyes emojis are added
 
@@ -36,6 +36,12 @@ jobs:
               "command": "retest",
               "permission": "write",
               "issue_type": "pull-request",
-              "repository": "tektoncd/pipeline"
+              "repository": "tektoncd/mcp-server"
+            },
+            {
+              "command": "cherry-pick",
+              "permission": "write",
+              "issue_type": "pull-request",
+              "repository": "tektoncd/mcp-server"
             }
           ]