[CI] Disable failing macOS-13 jobs

Ref: EnzymeAD#867.

Author: giordano

.github/workflows/CI.yml

@@ -56,6 +56,13 @@ jobs:
           - "IFRT"
         assertions:
           - false
+        exclude:
+          # Until <https://github.com/EnzymeAD/Reactant.jl/issues/867>
+          # is resolved.
+          - os: macOS-13
+            test_groups: core
+          - os: macOS-13
+            test_groups: integration
         include:
           - os: ubuntu-24.04
             version: '1.10'