fix(ci): update Docker action - fix master->main fallback tag, bump login-action to v3.7.0

- Fix Docker image tag fallback from 'master' to 'main' to match our default branch
- Bump docker/login-action from v3.5.0 to v3.7.0 for consistency with other workflows

.github/actions/build-push-image/action.yml

@@ -19,7 +19,7 @@ runs:
     - name: login to dockerhub
       id: login
       if: ${{ inputs.username != '' && inputs.password != '' }}
-      uses: docker/login-action@184bdaa0721073962dff0199f1fb9940f07167d1 # v3.5.0
+      uses: docker/login-action@c94ce9fb468520275223c153574b00df6fe4bcc9 # v3.7.0
       with:
         username: ${{ inputs.username }}
         password: ${{ inputs.password }}
@@ -30,7 +30,7 @@ runs:
         ZOMBIENET_IMAGE: "docker.io/pezkuwichain/zombienet:v1.3.105"
         IMAGE_TAG: docker.io/pezkuwichain/${{ inputs.image-name }}
       run: |
-        export DOCKER_IMAGES_VERSION=${{ github.event.pull_request.head.sha || 'master' }}
+        export DOCKER_IMAGES_VERSION=${{ github.event.pull_request.head.sha || 'main' }}
         if [[ ${{ github.event_name }} == "merge_group" ]]; then export DOCKER_IMAGES_VERSION="${GITHUB_SHA::8}"; fi
         docker build \
           --build-arg VCS_REF="${GITHUB_SHA}" \