Fix CI pipeline by using runner ubuntu-22.04 - cf. #1333

Author: Lucas-C

.github/workflows/continuous-integration-workflow.yml

@@ -10,7 +10,9 @@ on:  # cf. https://github.community/t/how-to-trigger-an-action-on-push-or-pull-r
 
 jobs:
   check-reference-pdf-files:
-    runs-on: ubuntu-latest
+    # Note: there is currently an issue with ubuntu-latest==ubuntu-24.04 / OpenSSL 3.0.13 / oscrypto:
+    # https://github.com/py-pdf/fpdf2/issues/1333
+    runs-on: ubuntu-22.04
     steps:
       - name: Checkout 🛎️
         uses: actions/checkout@v4