Upgrade zeromq & dashcore-lib

[pshenmic]

Issue

Outdated zeromq package makes project unable to npm install in Node 20+ environments:

#21 73.50 npm ERR! ../../nan/nan.h:2542:19: error: no matching function for call to 'v8::ObjectTemplate::SetAccessor(v8::Local<v8::String>&, void (*&)(v8::Local<v8::Name>, const v8::PropertyCallbackInfo<v8::Value>&), void (*&)(v8::Local<v8::Name>, v8::Local<v8::Value>, const v8::PropertyCallbackInfo<void>&), v8::Local<v8::Object>&, v8::AccessControl&, v8::PropertyAttribute&, Nan::imp::Sig&)'

Also, an outdated dashcore-lib package also used that does not support AssetUnlocks.

Things done

• Updated zeromq package to "@pshenmic/zeromq": "6.0.0-beta.22" (v6 compat + prebuilds)
• Updated dashcore-lib to "@dashevo/dashcore-lib": "^0.21.1" (latest version)
• Bump project version to 7.0.4