Update release notes

Author: danielsaidi

RELEASE_NOTES.md

@@ -7,6 +7,11 @@ This version makes the SDK use Swift 6.1.
 
 Due to actor isolation issues that can come from inheriting `Mock`, prefer to implement `Mockable` instead.
 
+### 💡 Behavior changes
+
+* `Mock` implements `Sendable`.
+* `Mockable` implements `Sendable`.
+
 
 
 ## 1.5

Tests/MockingKitTests/Foundation/MockUserDefaultsTests.swift

@@ -30,7 +30,7 @@ final class MockUserDefaultsTests: XCTestCase {
     }
 
     func testCanMockGettingData() {
-        let data = "123".data(using: .utf8)
+        let data = Data("123".utf8)
         defaults.registerResult(for: defaults.dataRef) { _ in data }
         XCTAssertEqual(defaults.data(forKey: "abc"), data)
     }