Version bump to 1.0.4

[wbingli]

Issue #, if available: N/A

Description of changes:. Release the latest change.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[wbingli]

The integration test failure is the reason why we need to release this new version. Need to update the default code gen version to 1.0.4 so the integ test will use the version from this repo instead of pulling 1.0.3 from remote maven repository.

Why the integ test success before?

Before it was successful because the integ test installs the 1.0.3 with the latest code during build, which overrides the remote 1.0.3.

[ammokhov]

interesting the build fails complaining that some of the ProxyClient methods were not implemented
this is the code from the stubs

      @Override
      public <RequestT extends AwsRequest, ResponseT extends AwsResponse>
      CompletableFuture<ResponseT>
      injectCredentialsAndInvokeV2Async(RequestT request, Function<RequestT, CompletableFuture<ResponseT>> requestFunction) {
        throw new UnsupportedOperationException();
      }