message: chore(docs): Fix bootstrap link
  Change link from pointing to the alpha bootstrap version to the latest website version.
diff: <p>Designed and built by the <a href="https://github.com/orgs/valor-software/teams/ng-team" target="_blank" rel="noopener">ng-team</a>
  with the help of our <a href="https://github.com/valor-software/ngx-bootstrap/graphs/contributors" target="_blank" rel="noopener">contributors.</a></p>
  <p>Code licensed under <a href="https://github.com/valor-software/ngx-bootstrap/blob/development/LICENSE" target="_blank" rel="noopener">MIT license conditions</a>, docs <a href="https://creativecommons.org/licenses/by/3.0/" target="_blank" rel="noopener">CC BY 3.0</a></p>
  - <p>Design and content of the documentation site heavily inspired by the <a target="_blank" rel="noopener" href="http://v4-alpha.getbootstrap.com/">original bootstrap</a> documentation</p>
  + <p>Design and content of the documentation site heavily inspired by the <a target="_blank" rel="noopener" href="https://getbootstrap.com/">original bootstrap.</a> documentation</p>
  </footer>
  