Use GITHUB_TOKEN for CI

Author: MattBlack85

.github/workflows/buildx.yml

@@ -46,7 +46,7 @@ jobs:
         with:
           registry: ${{ env.REGISTRY }}
           username: ${{ github.actor }}
-          password: ${{ secrets.CI_TOKEN }}
+          password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Derive image name
         id: img