exclude csst_proto in code style conformance test

pipelines/build.sh

@@ -22,7 +22,9 @@ echo "===================== show package info ====================="
 pip show $project
 
 echo "===================== download code style tests ====================="
-curl -O https://csst-tb.bao.ac.cn/code/csst-l1/csst_proto/-/raw/main/pipelines/test_codestyle.py
+if [ "$project" != "csst_proto" ]; then
+  curl -O https://csst-tb.bao.ac.cn/code/csst-l1/csst_proto/-/raw/main/pipelines/test_codestyle.py
+fi
 coverage run -m pytest
 
 echo "===================== make coverage ====================="