test: exclude some go fake files in ut coverage

Author: andyzhangx

.github/workflows/linux.yaml

@@ -48,4 +48,4 @@ jobs:
     - name: Send coverage
       env:
         COVERALLS_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-      run: goveralls -coverprofile=profile.cov -service=github -ignore=./pkg/blobfuse-proxy/pb
+      run: goveralls -coverprofile=profile.cov -service=github -ignore=pkg/blobfuse-proxy/pb