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
res = {}
        res['results'] = []
        res['msg'] = ''
        res['changed'] = False
        res['rc'] = 0
        pkgs = {}
        pkgs['update'] = []
        pkgs['install'] = []
        updates = {}
        obsoletes = {}
        update_all = False
        cmd = None
        
        if '*' in items:
            update_all = True
        rc, out, err = self.run_check_update()
        if rc == 0 and update_all:
            res['results'].append('Nothing to do here, all packages are up to date')
            return res
        elif rc == 100:
            updates, obsoletes = self.parse_check_update(out)
        elif rc == 1:
            res['msg'] = err
            res['rc'] = rc
            self.module.fail_json(**res)
        if update_all:
            cmd = self.yum_basecmd + ['update']
            will_update = set(updates.keys())