Update pubspec.yaml, CHANGELOG.md and expand deprecation notice (#378)

* Opt grpc_web_server.dart out of NNBD.

CHANGELOG.md

@@ -1,3 +1,13 @@
+## 2.8.0-dev
+
+* Added support for client interceptors, which can be configured through
+  `Client` constructor's `interceptors` parameter. Interceptors will be
+  executed by `Client.$createStreamingCall` and `Client.$createUnaryCall`.
+  Using interceptors requires regenerating client stubs using version 19.2.0 or
+  newer of protobuf compiler plugin.
+* `Client.$createCall` is deprecated because it does not invoke client
+  interceptors.
+
 ## 2.7.0
 
 * Added decoding/parsing of `grpc-status-details-bin` to pass all response

lib/src/client/client.dart

@@ -31,7 +31,12 @@ class Client {
       : _options = options ?? CallOptions(),
         _interceptors = List.unmodifiable(interceptors ?? Iterable.empty());
 
-  @Deprecated('createCall will be removed as it does not support interceptors')
+  @Deprecated(r'''This method does not invoke interceptors and is superseded
+by $createStreamingCall and $createUnaryCall which invoke interceptors.
+
+If you are getting this warning in autogenerated protobuf client stubs,
+regenerate these stubs using  protobuf compiler plugin version 19.2.0 or newer.
+''')
   ClientCall<Q, R> $createCall<Q, R>(
       ClientMethod<Q, R> method, Stream<Q> requests,
       {CallOptions options}) {

pubspec.yaml

@@ -1,7 +1,7 @@
 name: grpc
 description: Dart implementation of gRPC, a high performance, open-source universal RPC framework.
 
-version: 2.7.0
+version: 2.8.0-dev
 
 homepage: https://github.com/dart-lang/grpc-dart
 

test/grpc_web_server.dart

@@ -1,3 +1,4 @@
+// @dart = 2.3
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';