minor #5222 Upgrade Xcode (kubawerlos)

This PR was merged into the 2.15 branch.

Discussion
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Upgrade Xcode

Commits
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2866d0b Upgrade Xcode

Author: keradus

.circleci/config.yml

@@ -3,7 +3,8 @@ version: 2
 jobs:
     build:
         macos:
-            xcode: '11.7.0'
+            # https://circleci.com/docs/2.0/testing-ios/#supported-xcode-versions
+            xcode: '12.2.0'
         steps:
             - checkout