Revert "Updating ubuntu version to the latest based on CI failure"

Author: codingjeremy

.github/workflows/android.yml

@@ -24,7 +24,7 @@ jobs:
 
   build:
     name: Build
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-18.04
 
     steps:
       - uses: actions/checkout@v1