message: ops: fix message-relayer docker build
  The `exec` directory was removed, so no longer
  copy it over during the docker build.
diff: @@ -28,7 +28,6 @@ COPY --from=builder /optimism/packages/contracts/artifacts ./packages/contracts/
  WORKDIR /opt/optimism/packages/message-relayer
  COPY --from=builder /optimism/packages/message-relayer/dist ./dist
  COPY --from=builder /optimism/packages/message-relayer/package.json .
  -COPY --from=builder /optimism/packages/message-relayer/exec ./exec
  COPY --from=builder /optimism/packages/message-relayer/node_modules ./node_modules
  # copy this over in case you want to run alongside other services
  