chore: Use custom action to commit changes in CI instead of git commit (#85)

* chore: Use custom action to commit changes in CI instead of `git commit`

* Use `apify/actions/signed-commit`, simplify logic

* Remove unneeded fallback to `github.sha`

Author: fnesveda

.github/workflows/_update_release_metadata.yaml

@@ -55,7 +55,7 @@ jobs:
         name: Update changelog
         runs-on: ubuntu-latest
         outputs:
-            changelog_commitish: ${{ steps.commit.outputs.commit_long_sha || github.sha }}
+            changelog_commitish: ${{ steps.commit.outputs.commit_sha }}
         steps:
             - name: Checkout repository
               uses: actions/checkout@v6
@@ -79,8 +79,7 @@ jobs:
 
             - name: Commit changes
               id: commit
-              uses: EndBug/add-and-commit@v10
+              uses: apify/actions/signed-commit@v1.0.0
               with:
-                  author_name: Apify Release Bot
-                  author_email: noreply@apify.com
                   message: 'chore(release): Update changelog and package version [skip ci]'
+                  github-token: ${{ secrets.APIFY_SERVICE_ACCOUNT_GITHUB_TOKEN }}