Fix image tag export

Author: integrii

.github/workflows/publish.yaml

@@ -31,7 +31,7 @@ jobs:
         run: |
           SHORT_SHA=$(git rev-parse --short HEAD)
           IMAGE_TAG="kuberhealthy/ssh-check:${SHORT_SHA}"
-          echo "IMAGE_TAG=${{IMAGE_TAG}}" >> $GITHUB_ENV
+          echo "IMAGE_TAG=${IMAGE_TAG}" >> $GITHUB_ENV
 
       - name: Build and push
         uses: docker/build-push-action@v6