fix: add --amend flag (#83)

Author: t-aleksander

.github/workflows/build-docker.yml

@@ -75,6 +75,6 @@ jobs:
           tags='${{ env.GHCR_REPO }}:${{ github.sha }} ${{ steps.meta.outputs.tags }}'
           for tag in ${tags}
           do
-            docker manifest create ${tag} ${{ env.GHCR_REPO }}:${{ github.sha }}-amd64 ${{ env.GHCR_REPO }}:${{ github.sha }}-arm64
+            docker manifest create --amend ${tag} ${{ env.GHCR_REPO }}:${{ github.sha }}-amd64 ${{ env.GHCR_REPO }}:${{ github.sha }}-arm64
             docker manifest push ${tag}
           done