Update swiftpm branch to main

Author: shahmishal

utils/update_checkout/update-checkout-config.json

@@ -62,7 +62,7 @@
                 "cmark": "main",
                 "llbuild": "main",
                 "swift-tools-support-core": "main",
-                "swiftpm": "master",
+                "swiftpm": "main",
                 "swift-argument-parser": "0.3.0",
                 "swift-driver": "master",
                 "swift-syntax": "master",
@@ -92,7 +92,7 @@
                 "cmark": "main",
                 "llbuild": "main",
                 "swift-tools-support-core": "main",
-                "swiftpm": "master",
+                "swiftpm": "main",
                 "swift-argument-parser": "0.3.0",
                 "swift-driver": "master",
                 "swift-syntax": "master",
@@ -315,7 +315,7 @@
                 "cmark": "main",
                 "llbuild": "main",
                 "swift-tools-support-core": "main",
-                "swiftpm": "master",
+                "swiftpm": "main",
                 "swift-argument-parser": "0.3.0",
                 "swift-driver": "master",
                 "swift-syntax": "master",