Remove 20.04 from the list

Author: macumber

.github/workflows/app_build.yml

@@ -32,7 +32,7 @@ jobs:
       # fail-fast: Default is true, switch to false to allow one platform to fail and still run others
       fail-fast: false
       matrix:
-        os: [ubuntu-20.04, ubuntu-22.04, ubuntu-24.04, windows-2022, macos-13, macos-arm64]
+        os: [ubuntu-22.04, ubuntu-24.04, windows-2022, macos-13, macos-arm64]
         include:
         - os: ubuntu-22.04
           SELF_HOSTED: false