Fix actions.yml syntax

Author: datapythonista

action.yml

@@ -26,4 +26,4 @@ runs:
         ADD_COMMENT_URL: "https://api.github.com/repos/${{ github.repository }}/issues/${{ github.event.issue.number }}/comments"
         AUTHORIZATION_HEADER: "Authorization: token ${{ inputs.github_token }}"
         PREVIEWER_RESPONSE: "${{ steps.call-previewer.outputs.previewer-response }}"
-      run: curl -H "${AUTHORIZATION_HEADER}" -d "{\"body\": \"${PREVIEWER_RESPONSE}\"}" ${ADD_COMMENT_URL}
+      run: curl -H "${AUTHORIZATION_HEADER}" -d '{"body": "${{ env.PREVIEWER_RESPONSE}}"}' ${ADD_COMMENT_URL}