Update CI

No more old runners picking this from the queue :).

.github/workflows/main.yaml

@@ -12,9 +12,9 @@ on:
 jobs:
   coverage:
     name: Build
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
         with:
           submodules: recursive
       - name: Install dependencies