ci: change ubuntu runner in pr preview action (openscd#1677)

Author: noraeb

.github/workflows/pr-preview.yml

@@ -17,7 +17,7 @@ env:
 jobs:
   deploy-preview:
     permissions: write-all
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
       - name: Checkout
         uses: actions/checkout@v3