shouldn't require roles plugin

[stowns]

remove dependency on roles plugin

org.jenkinsci.plugins.workflow.cps.CpsCompilationErrorsException: startup failed:
/opt/bitnami/apps/jenkins/jenkins_home/jobs/banzai-cicd/jobs/banzai/branches/develop/builds/10/libs/BanzaiCICD/vars/gitOpsApprovalStage.groovy: 13: unable to resolve class com.michelin.cio.hudson.plugins.rolestrategy.RoleBasedAuthorizationStrategy 
 @ line 13, column 31.
     if (authStrategy instanceof com.michelin.cio.hudson.plugins.rolestrategy.RoleBasedAuthorizationStrategy) {