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
if self.releasever:
                self._yum_base.preconf.releasever = self.releasever
            if self.installroot != '/':
                
                
                
                self._yum_base.preconf.root = self.installroot
                self._yum_base.conf.installroot = self.installroot
            if self.conf_file and os.path.exists(self.conf_file):
                self._yum_base.preconf.fn = self.conf_file
            if os.geteuid() != 0:
                if hasattr(self._yum_base, 'setCacheDir'):
                    self._yum_base.setCacheDir()
                else:
                    cachedir = yum.misc.getCacheDir()
                    self._yum_base.repos.setCacheDir(cachedir)
                    self._yum_base.conf.cache = 0
            if self.disable_excludes:
                self._yum_base.conf.disable_excludes = self.disable_excludes
            
            
            self.yum_base.conf
            try:
                for rid in self.disablerepo:
                    self.yum_base.repos.disableRepo(rid)
                self._enablerepos_with_error_checking()
            except Exception as e:
                self.module.fail_json(msg="Failure talking to yum: %s" % to_native(e))
        return self._yum_base
    def po_to_envra(self, po):