hack,scripts: rename "master" branch references to "main"

Signed-off-by: Gyuho Lee <leegyuho@amazon.com>

Makefile

@@ -193,11 +193,11 @@ docker-test-coverage:
 
 # Example:
 #   make compile-with-docker-test
-#   ETCD_VERSION=v3-test make build-docker-release-master
-#   ETCD_VERSION=v3-test make push-docker-release-master
+#   ETCD_VERSION=v3-test make build-docker-release-main
+#   ETCD_VERSION=v3-test make push-docker-release-main
 #   gsutil -m acl ch -u allUsers:R -r gs://artifacts.etcd-development.appspot.com
 
-build-docker-release-master:
+build-docker-release-main:
 	$(info ETCD_VERSION: $(ETCD_VERSION))
 	cp ./Dockerfile-release.$(ARCH) ./bin/Dockerfile-release.$(ARCH)
 	docker build \
@@ -212,7 +212,7 @@ build-docker-release-master:
 	  gcr.io/etcd-development/etcd:$(ETCD_VERSION) \
 	  /bin/sh -c "/usr/local/bin/etcd --version && /usr/local/bin/etcdctl version"
 
-push-docker-release-master:
+push-docker-release-main:
 	$(info ETCD_VERSION: $(ETCD_VERSION))
 	docker push gcr.io/etcd-development/etcd:$(ETCD_VERSION)
 

hack/patch/README.md

@@ -1,6 +1,6 @@
 # ./hack/patch/cherrypick.sh
 
-Handles cherry-picks of PR(s) from etcd master to a stable etcd release branch automatically.
+Handles cherry-picks of PR(s) from etcd main to a stable etcd release branch automatically.
 
 ## Setup
 

hack/tls-setup/README.md

@@ -5,7 +5,7 @@ Defaults generate an ECDSA-384 root and leaf certificates for `localhost`. etcd
 **Instructions**
 
 1. Install git, go, and make
-2. Amend https://github.com/etcd-io/etcd/blob/master/hack/tls-setup/config/req-csr.json - IP's currently in the config should be replaced/added with IP addresses of each cluster node, please note 127.0.0.1 is always required for loopback purposes:
+2. Amend https://github.com/etcd-io/etcd/blob/main/hack/tls-setup/config/req-csr.json - IP's currently in the config should be replaced/added with IP addresses of each cluster node, please note 127.0.0.1 is always required for loopback purposes:
 ```json
 Example:
 {

scripts/release_mod.sh

@@ -87,8 +87,8 @@ function push_mod_tags_cmd {
   log_info "REMOTE_REPO:  ${REMOTE_REPO}"
 
   # Any module ccan be used for this
-  local master_version
-  master_version=$(go list -f '{{.Version}}' -m "${ROOT_MODULE}/api/v3")
+  local main_version
+  main_version=$(go list -f '{{.Version}}' -m "${ROOT_MODULE}/api/v3")
   local tags=()
 
   keyid=$(get_gpg_key) || return 2
@@ -101,8 +101,8 @@ function push_mod_tags_cmd {
     local subdir="${path//${ROOT_MODULE}\//}"
     local tag
     if [ -z "${version}" ]; then
-      tag="${master_version}"
-      version="${master_version}"
+      tag="${main_version}"
+      version="${main_version}"
     else
       tag="${subdir///v[23]/}/${version}"
     fi