[utils] Add support for swift-3.0-branch

Author: shahmishal

utils/update-checkout-config.json

@@ -155,7 +155,7 @@
             }
         },
         "swift-3.0-preview-5" : {
-            "aliases": ["swift-3.0-branch", "swift-3.0-preview-5-branch"],
+            "aliases": ["swift-3.0-preview-5-branch"],
             "repos": {
                 "llvm": "swift-3.0-branch",
                 "clang": "swift-3.0-branch",
@@ -171,6 +171,24 @@
                 "swift-integration-tests": "swift-3.0-preview-5-branch",
                 "swift-xcode-playground-support": "swift-3.0-preview-5-branch"
             }
+        },
+        "swift-3.0-branch" : {
+            "aliases": ["swift-3.0-branch"],
+            "repos": {
+                "llvm": "swift-3.0-branch",
+                "clang": "swift-3.0-branch",
+                "swift": "swift-3.0-branch",
+                "lldb": "swift-3.0-branch",
+                "cmark": "swift-3.0-branch",
+                "llbuild": "swift-3.0-branch",
+                "swiftpm": "swift-3.0-branch",
+                "compiler-rt": "swift-3.0-branch",
+                "swift-corelibs-xctest": "swift-3.0-branch",
+                "swift-corelibs-foundation": "swift-3.0-branch",
+                "swift-corelibs-libdispatch": "swift-3.0-branch",
+                "swift-integration-tests": "swift-3.0-branch",
+                "swift-xcode-playground-support": "swift-3.0-branch"
+            }
         }
     }
 }