add compatchecker comment

Author: lkdvos

.github/workflows/CompatCheck.yml

@@ -21,6 +21,8 @@ jobs:
     strategy:
       matrix:
         downgrade_mode: ['deps']
+        # TODO: this should be ['1.10', '1'] but that is currently broken:
+        # https://github.com/julia-actions/julia-downgrade-compat/issues/25
         julia-version: ['1.10', '1.12']
     steps:
       - uses: actions/checkout@v5