fix release workflow (#47)

Author: mwennrich

.github/workflows/dockerimages.yaml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v1
-    - uses: olegtarasov/get-tag@v1
+    - uses: olegtarasov/get-tag@v2.1
       id: tagName
     - uses: docker/setup-qemu-action@v1
     - uses: docker/setup-buildx-action@v1