Update HOWTO.md because of 'irc' version
Update HOWTO.md because of 'irc' version

Check my comment on commit 0454db3f85584e3d00de6d14fba9cdbdf55e6207. Because of the minimum version of irc change, Python 2.6 is no longer supported.
thelazier/electrum-dash-server,cryptapus/electrum-server,lbryio/lbryum-server,eXcomm/electrum-server,mazaclub/encompass-mercury,Verbalist/electrum-server,vcoin-project/electrum-server-vcn,GroestlCoin/electrum-grs-server,iswt/electrum-server,fireduck64/electrum-server,lbryio/lbryum-server,Kefkius/scallop-server,protonn/electrum-dgb-server,GroestlCoin/electrum-grs-server,cryptapus/electrum-server-myr,shsmith/electrum-server,sorce/electrum-server,bauerj/electrum-server,dashpay/electrum-dash-server,doged/encompass-mercury,Kefkius/scallop-server,shsmith/electrum-server,mazaclub/encompass-mercury,joshafest/electrum-fnx,sorce/electrum-server,argentumproject/electrum-arg-server,neoscoin/neos-electrum-server,argentumproject/electrum-arg-server,eXcomm/electrum-server,fireduck64/electrum-server,Kefkius/encompass-mercury,joshafest/electrum-fnx,Kefkius/encompass-mercury,repos-bitcoin/electrum-server,Verbalist/electrum-server,cryptapus/electrum-server-uno,iswt/electrum-server,doged/encompass-mercury,pooler/electrum-ltc-server,OverlordQ/electrum-server,repos-bitcoin/electrum-server,thelazier/electrum-dash-server,erasmospunk/electrum-server,bauerj/electrum-server,spesmilo/electrum-server,neoscoin/neos-electrum-server,pooler/electrum-ltc-server,vcoin-project/electrum-server-vcn,OverlordQ/electrum-server,spesmilo/electrum-server,erasmospunk/electrum-server,cryptapus/electrum-server-uno,dashpay/electrum-dash-server,protonn/electrum-dgb-server,cryptapus/electrum-server-myr,cryptapus/electrum-server