feat(generators): update java sdk and add maven signature settings

Author: rarokko

fern/apis/api/generators.yml

@@ -49,13 +49,17 @@ groups:
   java-sdk:
     generators:
       - name: fernapi/fern-java-sdk
-        version: 2.38.1
+        version: 2.38.6
         disable-examples: true
         output:
           location: maven
           coordinate: dev.vapi:server-sdk
           username: ${MAVEN_USERNAME}
           password: ${MAVEN_PASSWORD}
+          signature:
+              keyId: ${MAVEN_CENTRAL_SECRET_KEY_KEY_ID}
+              password: ${MAVEN_CENTRAL_SECRET_KEY_PASSWORD}
+              secretKey: ${MAVEN_CENTRAL_SECRET_KEY}
         github:
           repository: VapiAI/server-sdk-java
         config: