Fixed broken link to BasePlugin (#1270)
Fixed broken link to BasePlugin (#1270)

* Fixed broken link to BasePlugin

Updated the link to the BasePlugin.

* Update base plugin link

I should probably include the correct link if I'm fixing the link...
open-telemetry/opentelemetry-js,open-telemetry/opentelemetry-js,open-telemetry/opentelemetry-js,open-telemetry/opentelemetry-js