remove running of check-openmm-rc from PRs
remove running of check-openmm-rc from PRs

openpathsampling/openpathsampling,dwhswenson/openpathsampling,openpathsampling/openpathsampling,openpathsampling/openpathsampling,choderalab/openpathsampling,choderalab/openpathsampling,dwhswenson/openpathsampling,choderalab/openpathsampling,dwhswenson/openpathsampling,dwhswenson/openpathsampling,openpathsampling/openpathsampling