ci: Ran the Solaris action on macOS 13 instead of macOS 12 to avoid t…

…he non-working macOS 12 image.

See issue ppp-project#452 for more details.

Signed-off-by: RICCIARDI-Adrien <adrien.ricciardi@hotmail.fr>

.github/workflows/solaris.yaml

@@ -3,7 +3,7 @@ on: [push, pull_request]
 
 jobs:
   solaris:
-    runs-on: macos-12
+    runs-on: macos-13
     steps:
     - name: Checkout PPP sources
       uses: actions/checkout@v3