chore: add java sdk signing information

Author: dsinghvi

fern/generators.yml

@@ -45,9 +45,12 @@ groups:
           coordinate: io.intercom:intercom-java
           username: ${MAVEN_USERNAME}
           password: ${MAVEN_PASSWORD}
+          signature:
+            keyId: ${MAVEN_SIGNING_KEY_ID}
+            password: ${MAVEN_SIGNING_PASSWORD}
+            secretKey: ${MAVEN_SIGNING_KEY}
         github:
           repository: intercom/intercom-java
-          mode: pull-request
         config:
           enable-inline-types: true
           client-class-name: Intercom