ci: prefix labels with type (#1256)

Link: https://github.com/nix-community/stylix/discussions/1109#discussioncomment-13110835
Link: https://github.com/nix-community/stylix/pull/1256

Co-authored-by: NAHO <90870942+trueNAHO@users.noreply.github.com>
Reviewed-by: NAHO <90870942+trueNAHO@users.noreply.github.com>

.github/workflows/backport.yml

@@ -19,7 +19,7 @@ jobs:
         github.event.pull_request.merged == true &&
         (
           github.event_name != 'labeled' ||
-          startsWith('backport', github.event.label.name)
+          startsWith('backport: ', github.event.label.name)
         )
       )
 
@@ -42,5 +42,6 @@ jobs:
       - uses: korthout/backport-action@v3
         with:
           github_token: ${{ steps.app-token.outputs.token }}
+          label_pattern: "^backport: ([^ ]+)$"
           pull_title: "[${target_branch}] ${pull_title}"
           pull_description: "This is an automated backport of #${pull_number}."

.github/workflows/update-flake.yml

@@ -33,7 +33,7 @@ jobs:
           branch: update_flake_lock_action_${{ matrix.branch }}
           commit-msg: "flake: update all inputs"
           pr-title: "${{ startsWith(matrix.branch, 'release') && format('[{0}] ', matrix.branch) || '' }}stylix: update all flake inputs"   # yamllint disable-line rule:line-length
-          pr-labels: dependencies
+          pr-labels: "topic: dependencies"
           # yamllint disable rule:line-length
           pr-body: |
             Automated changes by the [update-flake-lock](https://github.com/DeterminateSystems/update-flake-lock) GitHub Action.