fix: struggle with ghcr

Author: blackheaven

action.yaml

@@ -40,8 +40,9 @@ runs:
     - name: Extract
       shell: bash
       run: |
-        docker pull ghcr.io/blackheaven/haskell-security-action:master
-        docker create --name dummy blackheaven/haskell-security-action:master
+        export IMG=ghcr.io/blackheaven/haskell-security-action:master
+        docker pull $IMG
+        docker create --name dummy $IMG
         docker cp -L dummy:/bin/github-action-scan github-action-scan
         docker rm -f dummy
     - name: Run Haskell Security Action