Update documentation.yml

Updated ubuntu version to build the documentation.

Author: perellonieto

.github/workflows/documentation.yml

@@ -6,7 +6,7 @@ on:
 jobs:
   build-n-deploy:
     name: Build and deploy
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-22.04
     steps:
     - name: Checkout code 🛎️
       uses: actions/[email protected]