Update build workflow to use ubuntu-latest

Responding to error: "This is a scheduled Ubuntu 20.04 retirement.
Ubuntu 20.04 LTS runner will be removed on 2025-04-15.
For more details, see actions/runner-images#11101""

Author: cartland

.github/workflows/android.yml

@@ -25,7 +25,7 @@ jobs:
 
   build:
     name: Build
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
 
     steps:
       - uses: actions/checkout@v1