Update workflow: remove branch default, detect only version tags

Author: Raffael Herrmann

.github/workflows/docker-build.yml

@@ -6,7 +6,6 @@ on:
       branch:
         description: 'Branch to build from'
         required: true
-        default: 'release-v1'
         type: string
       tag_as_latest:
         description: 'Tag image as latest'
@@ -24,13 +23,13 @@ jobs:
       with:
         ref: ${{ inputs.branch }}
 
-    - name: Get latest tag
+    - name: Get latest version tag
       id: get-tag
       run: |
         git fetch --tags
-        LATEST_TAG=$(git describe --tags --abbrev=0 2>/dev/null || echo "")
+        LATEST_TAG=$(git tag --list 'v[0-9]*.[0-9]*.[0-9]*' --sort=-version:refname | head -1)
         if [ -z "$LATEST_TAG" ]; then
-          echo "No tags found on branch ${{ inputs.branch }}"
+          echo "No version tags found on branch ${{ inputs.branch }}"
           exit 1
         fi
         echo "tag=$LATEST_TAG" >> $GITHUB_OUTPUT