Removing old ubuntu 18.04 github builder, adding 22.04

Author: jonoomph

.github/workflows/ci.yml

@@ -5,7 +5,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-18.04, ubuntu-20.04]
+        os: [ubuntu-20.04, ubuntu-22.04]
     defaults:
       run:
         shell: bash