fix github workflow conditions

Author: manuwei

.github/workflows/dockerhub.yml

@@ -28,15 +28,15 @@ jobs:
           password: ${{ secrets.DOCKER_HUB_ACCESS_TOKEN }}
 
       - name: Build and push latestPattern Atlas Api
-        if: ${{ steps.vars.outputs.tag }} == 'master'
+        if: ${{ steps.vars.outputs.tag == 'master' }}
         uses: docker/build-push-action@v2
         with:
           context: .
           push: true
           tags: planqk/latex-renderer:latest
-          
+
       - name: Build and push version of Pattern Atlas Api
-        if: ${{ steps.vars.outputs.tag }} != 'master'
+        if: ${{ steps.vars.outputs.tag != 'master' }}
         uses: docker/build-push-action@v2
         with:
           context: .