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
from __future__ import absolute_import, division, print_function
__metaclass__ = type
ANSIBLE_METADATA = {'metadata_version': '1.1',
                    'status': ['stableinterface'],
                    'supported_by': 'core'}
DOCUMENTATION = '''
---
module: yum
version_added: historical
short_description: Manages packages with the I(yum) package manager
description:
     - Installs, upgrade, downgrades, removes, and lists packages and groups with the I(yum) package manager.
     - This module only works on Python 2. If you require Python 3 support see the M(dnf) module.
options:
  use_backend:
    description:
      - This module supports C(yum) (as it always has), this is known as C(yum3)/C(YUM3)/C(yum-deprecated) by
        upstream yum developers. As of Ansible 2.7+, this module also supports C(YUM4), which is the
        "new yum" and it has an C(dnf) backend.
      - By default, this module will select the backend based on the C(ansible_pkg_mgr) fact.
    default: "auto"
    choices: [ auto, yum, yum4, dnf ]
    version_added: "2.7"