Remove the workaround for the linker issue in Swift 6.0

It's fixed in the main branch and cherry-picked to the 6.0 branch.

See swiftlang/swift#74277

Author: kateinoigakukun

Sources/CartonCore/Environment.swift

@@ -63,12 +63,6 @@ public enum Environment: String, CaseIterable {
     // for future dynamic linking support.
     parameters.otherSwiftcFlags += ["-static-stdlib"]
 
-    #if compiler(>=6.0) && compiler(<6.1)
-    // A workaround for the linker issue.
-    // https://github.com/swiftwasm/swift/issues/5580
-    parameters.otherLinkerFlags += ["-lswift_RegexParser"]
-    #endif
-
     switch self {
     case .command: break
     case .node, .browser:

Sources/CartonHelpers/DefaultToolchain.swift

@@ -13,7 +13,7 @@
 // limitations under the License.
 
 #if compiler(>=6.0)
-public let defaultToolchainVersion = "wasm-6.0-SNAPSHOT-2024-06-08-a"
+public let defaultToolchainVersion = "wasm-6.0-SNAPSHOT-2024-06-19-a"
 #elseif compiler(>=5.10)
 public let defaultToolchainVersion = "wasm-5.10.0-RELEASE"
 #else