[Update-checkout] Update swift-4.1-branch to checkout new branches

Author: shahmishal

utils/update-checkout-config.json

@@ -116,17 +116,17 @@
             "repos": {
                 "llvm": "swift-4.1-branch",
                 "clang": "swift-4.1-branch",
-                "swift": "master",
+                "swift": "swift-4.1-branch",
                 "lldb": "swift-4.1-branch",
-                "cmark": "master",
-                "llbuild": "master",
-                "swiftpm": "master",
+                "cmark": "swift-4.1-branch",
+                "llbuild": "swift-4.1-branch",
+                "swiftpm": "swift-4.1-branch",
                 "compiler-rt": "swift-4.1-branch",
-                "swift-corelibs-xctest": "master",
-                "swift-corelibs-foundation": "master",
-                "swift-corelibs-libdispatch": "master",
-                "swift-integration-tests": "master",
-                "swift-xcode-playground-support": "master",
+                "swift-corelibs-xctest": "swift-4.1-branch",
+                "swift-corelibs-foundation": "swift-4.1-branch",
+                "swift-corelibs-libdispatch": "swift-4.1-branch",
+                "swift-integration-tests": "swift-4.1-branch",
+                "swift-xcode-playground-support": "swift-4.1-branch",
                 "ninja": "release"
             }
         },