Run on latest ubuntu

Author: khellang

.github/workflows/build.yml

@@ -4,7 +4,7 @@ on: [push, pull_request]
 
 jobs:
   build:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     if: "!contains(github.event.head_commit.message, '[skip ci]')"
 
     env: