Bump to v0.6.1 [ci skip]
Bump to v0.6.1 [ci skip]

stijnster/appsignal-ruby,matrinox/appsignal-ruby,appsignal/appsignal-ruby,matrinox/appsignal-ruby,stijnster/appsignal-ruby,appsignal/appsignal-ruby,appsignal/appsignal,matrinox/appsignal-ruby,appsignal/appsignal,codefarmdev/haystack,q-m/appsignal,appsignal/appsignal-ruby,appsignal/appsignal-ruby,rranelli/appsignal,stijnster/appsignal-ruby,subvisual/appsignal