Try to fix the grafana/k6 Docker image label from v0.40.0 to 0.40.0

This way it will match with previous releases. It was broken in #2591 and the actual CI fix will happen in a separate bracnh and a proper PR. This is just a single commit we don't intend to merge in master, just to use the CI credentials to fix the issue for v0.40.0.

.github/workflows/fixup-docker.yml

@@ -0,0 +1,25 @@
+name: Fixup k6 v0.40.0 Docker image labels
+on:
+  push:
+    branches:
+      - fixup-docker-images
+
+defaults:
+  run:
+    shell: bash
+
+jobs:
+  re-publish-docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Log into Docker Hub
+        run: |
+          # Log into Docker Hub Registry
+          echo "${{ secrets.DOCKER_PASS }}" | docker login -u "${{ secrets.DOCKER_USER }}" --password-stdin
+
+      - name: Pull image, re-tag it and push again to Docker Hub
+        run: |
+          set -x
+          docker pull "grafana/k6:v0.40.0"
+          docker tag "grafana/k6:v0.40.0" "grafana/k6:0.40.0"
+          docker push "grafana/k6:0.40.0"