Merge pull request swiftlang#549 from apple/shahmishal/add-swift-5.5

Add support for Swift 5.5 branches

Author: shahmishal

common.py

@@ -47,6 +47,22 @@
         'swift-tools-support-core': 'main',
         'swift-crypto': '1.1.5',
     },
+    'release/5.5': {
+        'llvm-project': 'swift/release/5.5',
+        'swift': 'release/5.5',
+        'cmark': 'release/5.5',
+        'ninja': 'release',
+        'llbuild': 'release/5.5',
+        'swiftpm': 'release/5.5',
+        'swift-corelibs-libdispatch': 'release/5.5',
+        'swift-corelibs-foundation': 'release/5.5',
+        'swift-corelibs-xctest': 'release/5.5',
+        'swift-argument-parser': '0.4.3',
+        'swift-driver': 'release/5.5',
+        'yams': '4.0.2',
+        'swift-tools-support-core': 'release/5.5',
+        'swift-crypto': '1.1.5',
+    },
     'release/5.4': {
         'llvm-project': 'swift/release/5.4',
         'swift': 'release/5.4',