[CI] Set timeout of run-tests job to 60 minutes (EnzymeAD#843)

macOS runners are occasionally hanging, having a shorter timeout helps by making
the job fail earlier than waiting uselessly for 90 minutes, saving some time,
especially important since there are only 5 concurrent macOS runners across the
entire organisation.

Author: giordano

.github/workflows/CI.yml

@@ -113,6 +113,7 @@ jobs:
         env:
           JULIA_PKG_SERVER_REGISTRY_PREFERENCE: eager
       - name: "Run Tests"
+        timeout-minutes: 60
         run: |
           import Pkg
           Pkg.Registry.update()