[#1858] update release notes for 4.0.0rc2 with kerberos and coverage
[#1858] update release notes for 4.0.0rc2 with kerberos and coverage

PaulVanSchayck/irods,janiheikkinen/irods,PaulVanSchayck/irods,janiheikkinen/irods,janiheikkinen/irods,janiheikkinen/irods,PaulVanSchayck/irods,leesab/irods,janiheikkinen/irods,PaulVanSchayck/irods,leesab/irods,leesab/irods,janiheikkinen/irods,PaulVanSchayck/irods,leesab/irods,leesab/irods,janiheikkinen/irods,PaulVanSchayck/irods,leesab/irods,PaulVanSchayck/irods,janiheikkinen/irods,leesab/irods,janiheikkinen/irods,PaulVanSchayck/irods,PaulVanSchayck/irods