add etcd3 to supported providers

README.md

@@ -447,6 +447,13 @@ viper.SetConfigType("json") // because there is no file extension in a stream of
 err := viper.ReadRemoteConfig()
 ```
 
+#### etcd3
+```go
+viper.AddRemoteProvider("etcd3", "http://127.0.0.1:4001","/config/hugo.json")
+viper.SetConfigType("json") // because there is no file extension in a stream of bytes, supported extensions are "json", "toml", "yaml", "yml", "properties", "props", "prop", "env", "dotenv"
+err := viper.ReadRemoteConfig()
+```
+
 #### Consul
 You need to set a key to Consul key/value storage with JSON value containing your desired config.
 For example, create a Consul key/value store key `MY_CONSUL_KEY` with value:

viper.go

@@ -300,7 +300,7 @@ func NewWithOptions(opts ...Option) *Viper {
 func Reset() {
 	v = New()
 	SupportedExts = []string{"json", "toml", "yaml", "yml", "properties", "props", "prop", "hcl", "tfvars", "dotenv", "env", "ini"}
-	SupportedRemoteProviders = []string{"etcd", "consul", "firestore"}
+	SupportedRemoteProviders = []string{"etcd", "etcd3", "consul", "firestore"}
 }
 
 // TODO: make this lazy initialization instead
@@ -419,7 +419,7 @@ type RemoteProvider interface {
 var SupportedExts = []string{"json", "toml", "yaml", "yml", "properties", "props", "prop", "hcl", "tfvars", "dotenv", "env", "ini"}
 
 // SupportedRemoteProviders are universally supported remote providers.
-var SupportedRemoteProviders = []string{"etcd", "consul", "firestore"}
+var SupportedRemoteProviders = []string{"etcd", "etcd3", "consul", "firestore"}
 
 func OnConfigChange(run func(in fsnotify.Event)) { v.OnConfigChange(run) }
 func (v *Viper) OnConfigChange(run func(in fsnotify.Event)) {
@@ -573,7 +573,7 @@ func (v *Viper) AddConfigPath(in string) {
 
 // AddRemoteProvider adds a remote configuration source.
 // Remote Providers are searched in the order they are added.
-// provider is a string value: "etcd", "consul" or "firestore" are currently supported.
+// provider is a string value: "etcd", "etcd3", "consul" or "firestore" are currently supported.
 // endpoint is the url.  etcd requires http://ip:port  consul requires ip:port
 // path is the path in the k/v store to retrieve configuration
 // To retrieve a config file called myapp.json from /configs/myapp.json
@@ -604,7 +604,7 @@ func (v *Viper) AddRemoteProvider(provider, endpoint, path string) error {
 
 // AddSecureRemoteProvider adds a remote configuration source.
 // Secure Remote Providers are searched in the order they are added.
-// provider is a string value: "etcd", "consul" or "firestore" are currently supported.
+// provider is a string value: "etcd", "etcd3", "consul" or "firestore" are currently supported.
 // endpoint is the url.  etcd requires http://ip:port  consul requires ip:port
 // secretkeyring is the filepath to your openpgp secret keyring.  e.g. /etc/secrets/myring.gpg
 // path is the path in the k/v store to retrieve configuration