Build with older ubuntu for better compatibility (#14)

Author: vearutop

.github/workflows/release-assets.yml

@@ -14,7 +14,7 @@ env:
 jobs:
   build:
     name: Upload Release Assets
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - name: Install Go stable
         if: env.GO_VERSION != 'tip'