fix: links (#12706)

The linked GitHub projects contain a "main" instead of "master" branch.

Co-authored-by: Renke Christian von Seggern <[email protected]>

Author: rechvs

platform-includes/getting-started-primer/java.spring-boot.mdx

@@ -1,6 +1,6 @@
 <Alert>
 
-There are two variants of Sentry available for Spring Boot. If you're using our Gradle plugin it will pick the right dependency for you. If you're manually adding the dependency and using Spring Boot 2, use `sentry-spring-boot-starter` ([GitHub](https://github.com/getsentry/sentry-java/tree/master/sentry-spring-boot-starter)). If you're using Spring Boot 3, use `sentry-spring-boot-starter-jakarta` instead ([GitHub](https://github.com/getsentry/sentry-java/tree/master/sentry-spring-boot-starter-jakarta)).
+There are two variants of Sentry available for Spring Boot. If you're using our Gradle plugin it will pick the right dependency for you. If you're manually adding the dependency and using Spring Boot 2, use `sentry-spring-boot-starter` ([GitHub](https://github.com/getsentry/sentry-java/tree/main/sentry-spring-boot-starter)). If you're using Spring Boot 3, use `sentry-spring-boot-starter-jakarta` instead ([GitHub](https://github.com/getsentry/sentry-java/tree/main/sentry-spring-boot-starter-jakarta)).
 
 Sentry's integration with [Spring Boot](https://spring.io/projects/spring-boot) supports Spring Boot 2.1.0 and above to report unhandled exceptions as well as release and registration of beans. If you're on an older version, use [our legacy integration](/platforms/java/legacy/spring/).