support Xcode 13.0 and 13.1 RC 1

Author: WowbaggersLiquidLunch

Diff for: utils/build-script

@@ -56,7 +56,9 @@ _SUPPORTED_XCODE_BUILDS = [
     ("12.4", "12D4e"),
     ("12.5", "12E262"),
     ("13.0 beta", "13A5154h"),
-    ("13.0 beta 4", "13A5201i")
+    ("13.0 beta 4", "13A5201i"),
+    ("13.0", "13A233"),
+    ("13.1 RC 1", "13A1030d")
 ]
 
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