Add Grpc ProtoBuf support (request-response) (#1047)

* ProtoBuf

* .

* x

* ---

* x

* fx

* ...

* sc

* ...

* .

* groen

* x

* fix tests

* ok!?

* fix tests

* fix tests

* !

* x

* 6

* .

* x

* ivaluematcher

* transformer

* .

* sc

* .

* mapping

* x

* tra

* com

* ...

* .

* .

* .

* AddProtoDefinition

* .

* set

* grpahj

* .

* .

* IdOrText

* ...

* async

* async2

* .

* t

* nuget

* <PackageReference Include="ProtoBufJsonConverter" Version="0.2.0-preview-04" />

* http version

* tests

* .WithHttpVersion("2")

* <PackageReference Include="ProtoBufJsonConverter" Version="0.2.0" />

* HttpVersionParser

src/WireMock.Net/Matchers/NotNullOrEmptyMatcher.cs

@@ -17,6 +17,9 @@ public class NotNullOrEmptyMatcher : IObjectMatcher, IStringMatcher
     /// <inheritdoc />
     public MatchBehaviour MatchBehaviour { get; }
 
+    /// <inheritdoc />
+    public object Value { get; }
+
     /// <summary>
     /// Initializes a new instance of the <see cref="NotNullOrEmptyMatcher"/> class.
     /// </summary>
@@ -24,6 +27,7 @@ public class NotNullOrEmptyMatcher : IObjectMatcher, IStringMatcher
     public NotNullOrEmptyMatcher(MatchBehaviour matchBehaviour = MatchBehaviour.AcceptOnMatch)
     {
         MatchBehaviour = matchBehaviour;
+        Value = string.Empty;
     }
 
     /// <inheritdoc />