Docker: fix —version to include git information

GHA checkout needs to fetch full git history including tags for this to
work correctly.

.github/workflows/docker.yml

@@ -19,6 +19,8 @@ jobs:
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
 
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3