Update docker workflow

Author: yitzchak

.github/workflows/docker.yml

@@ -30,7 +30,6 @@ jobs:
         id: meta
         uses: docker/metadata-action@8e5442c4ef9f78752691e2d8f8d19755c6f78e81
         with:
-          context: docker/clasp/
           images: ghcr.io/clasp-developers/clasp
           tags: |
             type=raw,value=latest