style: rename github to gitea for gitea actions

Dockerfile

@@ -21,9 +21,13 @@ RUN cp -R $(nix-store -qR result/) /tmp/nix-store-closure
 # but they're fully self-contained so we don't need Nix anymore.
 FROM scratch
 
+# Label for container registry
+LABEL org.opencontainers.image.source=https://github.com/spotdemo4/trevstack
+
 WORKDIR /app
 
 # Copy /nix/store
 COPY --from=builder /tmp/nix-store-closure /nix/store
 COPY --from=builder /tmp/build/result /app
+
 CMD ["/app/bin/trevstack"]