Add git ref parameter to re-usable workflow

.github/workflows/eclipse-distro-build.yml

@@ -13,6 +13,11 @@ on:
         required: true
         default: 'snapshot'
         type: string
+      ref:
+        description: Git branch, tag, commit hash
+        required: false
+        default: 'main'
+        type: string
 
 jobs:
 
@@ -20,6 +25,7 @@ jobs:
     runs-on: [self-hosted, macOS]
     steps:
       - uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9
+        ref: ${{ inputs.ref }}
       - name: Set up JDK 17
         uses: actions/setup-java@5ffc13f4174014e2d4d4572b3d74c3fa61aeb2c2
         with: