Add OTP 20.1 to CI build matrix (#2566)
Add OTP 20.1 to CI build matrix (#2566)


eksperimental/phoenix,phoenixframework/phoenix,mitchellhenke/phoenix,michalmuskala/phoenix,Joe-noh/phoenix,dmarkow/phoenix,evax/phoenix,rafbgarcia/phoenix,keathley/phoenix,rafbgarcia/phoenix,0x00evil/phoenix,mschae/phoenix,gjaldon/phoenix,evax/phoenix,0x00evil/phoenix,pap/phoenix,Joe-noh/phoenix,phoenixframework/phoenix,mobileoverlord/phoenix,jwarwick/phoenix,pap/phoenix,Kosmas/phoenix,Kosmas/phoenix,phoenixframework/phoenix,gjaldon/phoenix,trarbr/phoenix,Gazler/phoenix,jwarwick/phoenix,mobileoverlord/phoenix,stevedomin/phoenix,trarbr/phoenix,rafbgarcia/phoenix,Gazler/phoenix,stevedomin/phoenix,dmarkow/phoenix,mschae/phoenix,optikfluffel/phoenix,bsmr-erlang/phoenix,nshafer/phoenix,korobkov/phoenix,mitchellhenke/phoenix,nshafer/phoenix,eksperimental/phoenix,bsmr-erlang/phoenix,0x00evil/phoenix,optikfluffel/phoenix,michalmuskala/phoenix,korobkov/phoenix,nshafer/phoenix,keathley/phoenix,optikfluffel/phoenix