Upgrade to unix-dgram 2.0.6 for node 18 support

[DZDomi]

Hey,

In order to have support for node 18, the unix-dram package needs to be upgraded to 2.0.6, which came out yesterday.

Currently the build will fail with the following error message on node 18.11.0:

../../nan/nan_typedarray_contents.h:34:43: error: ‘class v8::ArrayBuffer’ has no member named ‘GetContents’
   34 |       data   = static_cast<char*>(buffer->GetContents().Data()) + byte_offset;
      |                                           ^~~~~~~~~~~

[DZDomi]

Thanks for taking the time to upgrade ❤️ , already updated and works fine 👍🏻