Use correct buf login command (#2466)

This was moved to buf registry login in the
v1.0.0 release candidates

.circleci/config.yml

@@ -150,7 +150,7 @@ jobs:
       - image: bufbuild/buf:1.0.0-rc8
     steps:
       - checkout
-      - run: echo "${BUF_API_TOKEN}" | buf login --username grpcgatewaybot --token-stdin
+      - run: echo "${BUF_API_TOKEN}" | buf registry login --username grpcgatewaybot --token-stdin
       # Limit pushes to protoc-gen-openapiv2 files. This is a total hack.
       # It excludes all the files that we don't want to publish, just for the push step.
       - run: echo -e "    - examples\n    - internal\n    - runtime" >> buf.yaml