Merge pull request #10548 from apple/swift-4-update-checkout-branch

[4.0] [Utils] Update the branch names in update-checkout

Author: shahmishal

utils/update-checkout-config.json

@@ -129,6 +129,25 @@
                 "swift-xcode-playground-support": "swift-4.0-branch",
                 "ninja": "release"
             }
+        },
+         "swift-4.0-branch-06-23-2017" : {
+            "aliases": ["swift-4.0-branch-06-23-2017"],
+            "repos": {
+                "llvm": "swift-4.0-branch-06-23-2017",
+                "clang": "swift-4.0-branch-06-23-2017",
+                "swift": "swift-4.0-branch-06-23-2017",
+                "lldb": "swift-4.0-branch-06-23-2017",
+                "cmark": "swift-4.0-branch",
+                "llbuild": "swift-4.0-branch",
+                "swiftpm": "swift-4.0-branch",
+                "compiler-rt": "swift-4.0-branch-06-23-2017",
+                "swift-corelibs-xctest": "swift-4.0-branch",
+                "swift-corelibs-foundation": "swift-4.0-branch",
+                "swift-corelibs-libdispatch": "swift-4.0-branch",
+                "swift-integration-tests": "swift-4.0-branch",
+                "swift-xcode-playground-support": "swift-4.0-branch",
+                "ninja": "release"
+            }
         }
     }
 }