Hi, what version of camunda run are you using? Connector library was not included by default and in oast versions, you needed to add the library yourself…
I am not sure what you are trying to achieve with using Connectors. In general Connectors where introduced before External Tasks and wanted to provide an option to make REST Calls without using Java. This said Connectors are a wrapper around the Java layer. The purpose of Camundarun is to use it Standalone and not to connect with the Java API but with the REST API. This way Connectors where not introduced into CamundaRun. As @Webcyberrob mention you can still add the lib to it. In the 7.17 release they will be available out of the box again.
I mentioned above that now there exist also the possibility to use External Tasks to make REST calls in other languages. This might be also a way to go. @Niall and I created a github repo explaining the different options you have to make REST calls in Camunda. There are some benefits in using External Tasks over connectors.
I hope this helps
Cheers
Nele