fix: Use custom action for updating flake.lock

.github/workflows/update.yml

@@ -16,15 +16,37 @@ jobs:
         uses: https://github.com/DeterminateSystems/magic-nix-cache-action@main
         with:
           fail-mode: true
+
       - name: Update flake.lock
-        uses: https://github.com/DeterminateSystems/update-flake-lock@main
+        id: update
+        run: |
+          nix flake update 2>&1 | awk '
+            /^• Updated input/ {in_update = 1; print; next}
+            in_update && !/^warning:/ {print}
+            /^$/ {in_update = 0}
+          ' > update.log
+          echo "update_log=$(cat update.log)" >> $GITHUB_OUTPUT
+          rm update.log
+
+      - name: Create Pull Request
+        id: create-pull-request
+        uses: peter-evans/create-pull-request@v7
         with:
-          # inputs: dzgui dzgui-testing # We'll see whether I want to limit the updates to dzgui
             token: ${{ secrets.FORGEJO_TOKEN_FOR_UPDATES  }}
-          pr-title: "Update flake.lock"
+            commit-message: Update `flake.lock`
-          pr-assignees: jiriks74
+            title: Update `flake.lock`
-          pr-labels: |
+            body: |
-            flake.lock
+              - The following Nix Flake inputs were updated
-            automated
+
+              ```
+              ${{ steps.update.outputs.update_log }}
+              ```
+  
+              Auto-generated by [update.yml][1] with the help of
+              [create-pull-request][2]
+  
+              [1]: https://forgejo.stefka.eu/jiriks74/update-flake-lock
+              [2]: https://github.com/peter-evans/create-pull-request
+            branch: update-flake-lock
       - name: Print PR number
-        run: echo Pull request number is ${{ steps.update.outputs.pull-request-number }}.
+        run: echo Pull request number is ${{ steps.create-pull-request.outputs.pull-request-number }}.