I am using the yum module to lock the release version for a RHEL 7.6 machine to 7.7 version. However the yum --releasever option does not set the release version to 7.7. I am using Ansible 2.7.10 version.
Here is the discussion regarding the issue: 
https://access.redhat.com/discussions/4774501

ISSUE TYPE
Bug Report

COMPONENT NAME
yum --releasever

ANSIBLE VERSION
2.7.10 

STEPS TO REPRODUCE
name: installing updated packages
yum:
name: '*'
state: latest
releasever: '7.7'

ACTUAL RESULTS
Play runs successfully however it does not update the release version of the server
cmd = self.yum_basecmd + [action] + pkgs
        if self.module.check_mode:
            self.module.exit_json(changed=True, results=res['results'], changes=dict(installed=pkgs))
        else:
            res['changes'] = dict(installed=pkgs)
        lang_env = dict(LANG='C', LC_ALL='C', LC_MESSAGES='C')