Rename `metadata_master_container_path` to `metadata_main_container_path`

Library/Homebrew/cask/cask.rb

@@ -102,11 +102,11 @@ module Cask
 
     def installed_caskfile
       installed_version = timestamped_versions.last
-      metadata_master_container_path.join(*installed_version, "Casks", "#{token}.rb")
+      metadata_main_container_path.join(*installed_version, "Casks", "#{token}.rb")
     end
 
     def config_path
-      metadata_master_container_path/"config.json"
+      metadata_main_container_path/"config.json"
     end
 
     def caskroom_path

Library/Homebrew/cask/installer.rb

@@ -538,7 +538,7 @@ module Cask
 
         @cask.metadata_versioned_path.rmdir_if_possible
       end
-      @cask.metadata_master_container_path.rmdir_if_possible unless upgrade?
+      @cask.metadata_main_container_path.rmdir_if_possible unless upgrade?
 
       # toplevel staged distribution
       @cask.caskroom_path.rmdir_if_possible unless upgrade?

Library/Homebrew/cask/metadata.rb

@@ -9,8 +9,8 @@ module Cask
     METADATA_SUBDIR = ".metadata"
     TIMESTAMP_FORMAT = "%Y%m%d%H%M%S.%L"
 
-    def metadata_master_container_path
-      @metadata_master_container_path ||= caskroom_path.join(METADATA_SUBDIR)
+    def metadata_main_container_path
+      @metadata_main_container_path ||= caskroom_path.join(METADATA_SUBDIR)
     end
 
     def metadata_versioned_path(version: self.version)
@@ -18,7 +18,7 @@ module Cask
 
       raise CaskError, "Cannot create metadata path with empty version." if cask_version.empty?
 
-      metadata_master_container_path.join(cask_version)
+      metadata_main_container_path.join(cask_version)
     end
 
     def metadata_timestamped_path(version: self.version, timestamp: :latest, create: false)