Set GitHub action to use Ubuntu 22.04

Author: petrusck

.github/workflows/swift.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os: [ubuntu-22.04, macos-latest]
         swift: ["5.9.0"]
     steps:
       - uses: actions/checkout@v2