Use ubuntu-22.04

Author: ralfhandl

.github/workflows/respec.yaml

@@ -19,7 +19,7 @@ jobs:
   respec:
     if: github.repository == 'ralfhandl/Overlay-Specification'
 
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
 
     steps:
     - name: Generate a token