Bump to v0.5.0.beta4 [ci skip]
Bump to v0.5.0.beta4 [ci skip]

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