README.md: added build status for existing releases and master
README.md: added build status for existing releases and master

Signed-off-by: Nikos Mavrogiannopoulos <df6e1a462b5068e7cd37b5ebdba5d9f6b4da01fc@redhat.com>

nmav/fedora-crypto-policies,nmav/fedora-crypto-policies,nmav/fedora-crypto-policies,nmav/fedora-crypto-policies,nmav/fedora-crypto-policies