Revise CODEOWNERS with new branch management rules

Updated CODEOWNERS to reflect new ownership and guidelines for the main branch.

Author: shahmishal

.github/CODEOWNERS

@@ -7,23 +7,14 @@
 # Each line is a file pattern followed by one or more owners.
 # Order is important. The last matching pattern has the most precedence.
 
-# Owner of anything in SwiftDriver not owned by anyone else.
-* @artemcm @owenv @DougGregor @compnerd
-
-# Explicit Modules
-*ExplicitModuleBuilds* @artemcm @cachemeifyoucan @owenv
-
-# Planning
-*Jobs* @artemcm @owenv @cachemeifyoucan
-
-# Executor
-*SwiftDriverExecution* @owenv @artemcm
-
-# Incremental Builds
-*IncrementalCompilation* @owenv @artemcm
-
-# Toolchains
-*Toolchains* @compnerd @DougGregor @artemcm @owenv
-
-# SDK Interface Compilation
-*swift-build-sdk-interfaces* @nkcsgexi @artemcm
+# The main branch is now in convergence, which means major changes, such as
+# large refactoring or new features, should be avoided. This strategy is
+# intended to maintain the stability of the Swift 6.4 release leading up to
+# the May 4th branch. For any work that requires broad changes or introduces
+# new features, create a feature branch and open a draft pull request.
+# All updates to the swiftlang/swift repository’s main branch require
+# approval from the release managers. A pull request targeting swiftlang/swift
+# will automatically add release managers. You can also contact them
+# via @release-managers in the forum group.
+
+* @swiftlang/swift-branch-managers