Fix outdated branch name

Author: quaff

docs/modules/ROOT/pages/discovery-client.adoc

@@ -1,7 +1,7 @@
 [[discoveryclient-for-kubernetes]]
 = DiscoveryClient for Kubernetes
 
-This project provides an implementation of https://github.com/spring-cloud/spring-cloud-commons/blob/master/spring-cloud-commons/src/main/java/org/springframework/cloud/client/discovery/DiscoveryClient.java[Discovery Client]
+This project provides an implementation of https://github.com/spring-cloud/spring-cloud-commons/blob/main/spring-cloud-commons/src/main/java/org/springframework/cloud/client/discovery/DiscoveryClient.java[Discovery Client]
 for https://kubernetes.io[Kubernetes].
 This client lets you query Kubernetes endpoints (see https://kubernetes.io/docs/user-guide/services/[services]) by name.
 A service is typically exposed by the Kubernetes API server as a collection of endpoints that represent `http` and `https` addresses and that a client can

docs/modules/ROOT/pages/examples.adoc

@@ -10,7 +10,7 @@ The same applies for `PropertySourceLocator`, where you need to add to the class
 
 The following projects highlight the usage of these dependencies and demonstrate how you can use these libraries from any Spring Boot application:
 
-* https://github.com/spring-cloud/spring-cloud-kubernetes/tree/master/spring-cloud-kubernetes-examples[Spring Cloud Kubernetes Examples]: the ones located inside this repository.
+* https://github.com/spring-cloud/spring-cloud-kubernetes/tree/main/spring-cloud-kubernetes-examples[Spring Cloud Kubernetes Examples]: the ones located inside this repository.
 * Spring Cloud Kubernetes Full Example: Minions and Boss
 	** https://github.com/salaboy/spring-cloud-k8s-minion[Minion]
 	** https://github.com/salaboy/spring-cloud-k8s-boss[Boss]

docs/modules/ROOT/pages/pod-health-indicator.adoc

@@ -2,7 +2,7 @@
 = Pod Health Indicator
 :page-section-summary-toc: 1
 
-Spring Boot uses https://github.com/spring-projects/spring-boot/blob/master/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/HealthEndpoint.java[`HealthIndicator`] to expose info about the health of an application.
+Spring Boot uses https://github.com/spring-projects/spring-boot/blob/main/spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/HealthEndpoint.java[`HealthIndicator`] to expose info about the health of an application.
 That makes it really useful for exposing health-related information to the user and makes it a good fit for use as https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-probes/[readiness probes].
 
 The Kubernetes health indicator (which is part of the core module) exposes the following info:

docs/modules/ROOT/pages/property-source-config/configmap-propertysource.adoc

@@ -3,7 +3,7 @@
 
 Kubernetes provides a resource named https://kubernetes.io/docs/user-guide/configmap/[`ConfigMap`] to externalize the
 parameters to pass to your application in the form of key-value pairs or embedded `application.properties` or `application.yaml` files.
-The link:https://github.com/spring-cloud/spring-cloud-kubernetes/tree/master/spring-cloud-kubernetes-fabric8-config[Spring Cloud Kubernetes Config] project makes Kubernetes `ConfigMap` instances available
+The link:https://github.com/spring-cloud/spring-cloud-kubernetes/tree/main/spring-cloud-kubernetes-fabric8-config[Spring Cloud Kubernetes Config] project makes Kubernetes `ConfigMap` instances available
 during application startup and triggers hot reloading of beans or Spring context when changes are detected on
 observed `ConfigMap` instances.