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 not pkgs:
                    e, m, _ = self.yum_base.pkgSack.matchPackageNames([req_spec])
                    pkgs.extend(e)
                    pkgs.extend(m)
                    e, m, _ = self.yum_base.rpmdb.matchPackageNames([req_spec])
                    pkgs.extend(e)
                    pkgs.extend(m)
            except Exception as e:
                self.module.fail_json(msg="Failure talking to yum: %s" % to_native(e))
            return set(self.po_to_envra(p) for p in pkgs)
        else:
            myrepoq = list(repoq)
            r_cmd = ['--disablerepo', ','.join(self.disablerepo)]
            myrepoq.extend(r_cmd)
            r_cmd = ['--enablerepo', ','.join(self.enablerepo)]
            myrepoq.extend(r_cmd)
            cmd = myrepoq + ["--qf", qf, "--whatprovides", req_spec]
            rc, out, err = self.module.run_command(cmd)
            cmd = myrepoq + ["--qf", qf, req_spec]
            rc2, out2, err2 = self.module.run_command(cmd)
            if rc == 0 and rc2 == 0:
                out += out2
                pkgs = set([p for p in out.split('\n') if p.strip()])
                if not pkgs:
                    pkgs = self.is_installed(repoq, req_spec, qf=qf)
                return pkgs
            else:
                self.module.fail_json(msg='Error from repoquery: %s: %s' % (cmd, err + err2))
        return set()
    def transaction_exists(self, pkglist):