function getVersionRegexBySpecificationVersion(specificationVersion) {
  let versionRegExp;
  if (compareVersion(specificationVersion, '2.0')) {
    versionRegExp = getVersionRegexp(VERSION_20);
  }
  else if (compareVersion(specificationVersion, '3.1')) {
    versionRegExp = getVersionRegexp(VERSION_31);
  }
  else {
    versionRegExp = getVersionRegexp(VERSION_30);
  }
  return versionRegExp;
}
Determins the version regex according to the specificationVersion
@param {string} specificationVersion the string of the desired version
@returns {object} the resultant regular expresion using the provided data