Allow releasing a non-master branch.

Author: yruslan

.github/workflows/release.yaml

@@ -31,7 +31,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: master
+          ref: ${{ github.head_ref || github.ref_name }}
 
       - name: Setup JDK and sbt
         uses: actions/setup-java@v4
@@ -72,7 +72,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: master
+          ref: ${{ github.head_ref || github.ref_name }}
 
       - name: Checkout the release branch
         id: release_branch3