Fix docker links

Author: nosan

spring-boot-project/spring-boot-docker-compose/src/main/java/org/springframework/boot/docker/compose/core/Regex.java

@@ -25,10 +25,10 @@
  * @author Scott Frederick
  * @author Phillip Webb
  * @see <a href=
- * "https://github.com/docker/distribution/blob/master/reference/reference.go">Docker
+ * "https://github.com/distribution/reference/blob/main/reference.go">Docker
  * grammar reference</a>
  * @see <a href=
- * "https://github.com/docker/distribution/blob/master/reference/regexp.go">Docker grammar
+ * "https://github.com/distribution/reference/blob/main/regexp.go">Docker grammar
  * implementation</a>
  * @see <a href=
  * "https://stackoverflow.com/questions/37861791/how-are-docker-image-names-parsed">How