Update branch name (#10)

Author: xqrzd

.github/workflows/ci.yml

@@ -26,7 +26,7 @@ jobs:
     needs: linux_build
     runs-on: ubuntu-20.04
 
-    if: github.ref == 'refs/heads/master'
+    if: github.ref == 'refs/heads/main'
     steps:
     - uses: actions/checkout@v2
     - name: Setup .NET Core