Resolves #422

Problem

Trying to java -jar a fat JAR built with something like maven-assembly-plugin users will see this error as soon as they try to instantiate WeaviateClient:

Exception in thread "main" java.lang.IllegalArgumentException: Address types of NameResolver 'unix' for 'grpc-
blahblahblah.gcp.weaviate.cloud:443' not supported by transport
        at io.grpc.internal.ManagedChannelImplBuilder.getNameResolverProvider(ManagedChannelImplBuilder.java:8
50)
        at io.grpc.internal.ManagedChannelImplBuilder.build(ManagedChannelImplBuilder.java:700)
        at io.grpc.ForwardingChannelBuilder2.build(ForwardingChannelBuilder2.java:272)
        at io.weaviate.client6.v1.internal.grpc.DefaultGrpcTransport.buildChannel(DefaultGrpcTransport.java:92
)
        at io.weaviate.client6.v1.internal.grpc.DefaultGrpcTransport.<init>(DefaultGrpcTransport.java:24)
        at io.weaviate.client6.v1.api.WeaviateClient.<init>(WeaviateClient.java:26)
        at io.weaviate.client6.v1.api.WeaviateClient.custom(WeaviateClient.java:54)

After some investigation (and with invaluable help from @Dabz) the problem is this:

io.grpc uses META-INF/services to dynamically load NameResolver providers. When building a fat JAR, plugins like maven-assembly-plugin won't merge overlapping config files without an additional configuration on the end-user's side.

This comment is also very insightful.

Solution

While configuring the plugin is not difficult and we could document this in our README, we will do our users one better:
using maven-shade-plugin we can distribute a shaded version of client6 with all its' dependencies' configurations resolved in advance (in addition to the 'slim' version of the lib).

Now, when trying to build a fat JAR all that our users will need to do is include <classifier>all</classifier> tag to client6 block.

<dependency>
  <groupId>io.weaviate</groupId>
  <artifactId>client6</artifactId>
  <version>6.0.0-XXX</artifactId>
  <classifier>all</classifier>
<dependency>