Revert "exclude bair.berkeley.edu temporarily (#2702)" (#2734)

This reverts commit 370972ccd939f72b0529a3f493b27e6ac55020fa.

markdown-link-check.config.json

         {
             "pattern": "^https://developer.nvidia.com/compute/machine-learning/cudnn/secure",
             "comment": "Requires login"
-        },
-        {
-            "pattern": "^https?://bair.berkeley.edu",
-            "comment": "Temporary berkeley outage"
         }
     ]
 }