Missed a quote

Signed-off-by: Dimitris Karakasilis <[email protected]>

.github/workflows/image.yaml

@@ -26,7 +26,7 @@ jobs:
           sudo apt update && sudo apt install -y jq
       - id: set-matrix
         run: |
-          content=`cat .github/flavors.json  | jq 'map(select(.variant == "core"))'
+          content=`cat .github/flavors.json  | jq 'map(select(.variant == "core"))'`
           # the following lines are only required for multi line json
           # the following lines are only required for multi line json
           content="${content//'%'/'%25'}"