Fetching base branch on CI as well as on local machine

fetchBaseBranch.js

/*
 * Need to add refs and then fetch, as Jenkins does not allow to fetch other barnches
 */
async function fetchBaseBranch(baseBranch) {
  try {
    console.log("Fetching ${baseBranch} from remote");
    const addBaseRefs = `git config --add remote.origin.fetch +refs/heads/${baseBranch}:refs/remotes/origin/${baseBranch}`;
    const fetchBase = `git fetch --no-tags origin +refs/heads/${baseBranch}:refs/remotes/origin/${baseBranch}`;
    const command = `${addBaseRefs} && ${fetchBase}`;
    await exec(command);
  } catch (ex) {
    console.log("Failed in fetching changed files", ex);
    return null;
  }
}