Illegal character in hostname error when using consul and docker

I'm having microservices running in Docker containers and I use Consul as service discovery. Every now and then the GRPC calls between the services are failing and I get this exception:

```
io.grpc.internal.ProxyDetectorImpl.detectProxy Failed to construct URI for proxy lookup, proceeding without proxy
java.net.URISyntaxException: Illegal character in hostname at index 19: https://xxx2_xx-yyy-zzz_1.www2_ppp:8192
at java.net.URI$Parser.fail(URI.java:2848)
at java.net.URI$Parser.parseHostname(URI.java:3387)
at java.net.URI$Parser.parseServer(URI.java:3236)
at java.net.URI$Parser.parseAuthority(URI.java:3155)
at java.net.URI$Parser.parseHierarchical(URI.java:3097)
at java.net.URI$Parser.parse(URI.java:3053)
at java.net.URI.(URI.java:673)
at io.grpc.internal.ProxyDetectorImpl.detectProxy(ProxyDetectorImpl.java:128)
at io.grpc.internal.ProxyDetectorImpl.proxyFor(ProxyDetectorImpl.java:118)
at io.grpc.internal.InternalSubchannel.startNewTransport(InternalSubchannel.java:207)
at io.grpc.internal.InternalSubchannel.obtainActiveTransport(InternalSubchannel.java:188)
at io.grpc.internal.ManagedChannelImpl$SubchannelImpl.requestConnection(ManagedChannelImpl.java:1130)
at io.grpc.PickFirstBalancerFactory$PickFirstBalancer.handleResolvedAddressGroups(PickFirstBalancerFactory.java:79)
...
```

### What version of gRPC are you using?
1.10.0

### What did you expect to see?
I would expect that when the DNS name contains non-URI friendly characters, the GRPC call to continue to work and encode the URI properly.

Inizia con io.grpc.internal.ProxyDetectorImpl in corrispondenza del problema segnalato vicino alla riga 128, quindi riproduci la ricerca del proxy utilizzando il nome host mostrato nello stack trace. Il lavoro è completato quando la chiamata gRPC continua a funzionare se il nome DNS contiene i caratteri segnalati e l’URI viene gestita correttamente.

Scritto dal modello di indicizzazione a partire dal testo della issue.