feat(worker): add 'use_ipv4' option for rsync provider

worker/config.go

@@ -123,6 +123,7 @@ type mirrorConfig struct {
 
 	Command       string `toml:"command"`
 	UseIPv6       bool   `toml:"use_ipv6"`
+	UseIPv4       bool   `toml:"use_ipv4"`
 	ExcludeFile   string `toml:"exclude_file"`
 	Username      string `toml:"username"`
 	Password      string `toml:"password"`