Add joelmoss to contributors
Add joelmoss to contributors

rwhitmire/messenger,npmcomponent/HubSpot-messenger,npmcomponent/HubSpot-messenger,giobero999/messenger,HubSpot/messenger,leegilon/messenger,freakynit/messenger,giobero999/messenger,leegilon/messenger,freakynit/messenger,dieface/messenger,rwhitmire/messenger,dieface/messenger,HubSpot/messenger