Update XCode version on CircleCI (#1103)

12.2 is being deprecated

Author: sbc100

.circleci/config.yml

@@ -49,7 +49,7 @@ jobs:
             test/test.py
   test-mac:
     macos:
-      xcode: "12.2.0"
+      xcode: "12.5.1"
     environment:
       EMSDK_NOTTY: "1"
       # Without this, any `brew installl` command will result in self-update of
@@ -193,7 +193,7 @@ jobs:
 
   test-bazel-mac:
     macos:
-      xcode: "12.2.0"
+      xcode: "12.5.1"
     environment:
       EMSDK_NOTTY: "1"
       HOMEBREW_NO_AUTO_UPDATE: "1"