build: upgrade ds-spring-user-framework to 4.2.0 stable release

Replace 4.1.1-SNAPSHOT with the stable 4.2.0 release which includes
the WebAuthn/Passkey support needed by this branch.

Author: devondragon

build.gradle

@@ -39,7 +39,7 @@ repositories {
 
 dependencies {
     // DigitalSanctuary Spring User Framework
-    implementation 'com.digitalsanctuary:ds-spring-user-framework:4.1.1-SNAPSHOT'
+    implementation 'com.digitalsanctuary:ds-spring-user-framework:4.2.0'
 
     // WebAuthn support (Passkey authentication)
     implementation 'org.springframework.security:spring-security-webauthn'