fix: use unauthenticated URL to check if branch is up to date

In case the authentication token provided is unauthorized the call to `isBranchUpToDate` will fail due to lack of read permission if that URL is used. As a result the error about outdated local branch will be reported instead of the one about missing permission.
By using the original (unauthenticated) URL `isBranchUpToDate` shouldn't fail due to permission as it requires only read permissions, that are necessarly present as the CI wass able to clone the repo.

lib/git.js

@@ -145,15 +145,14 @@ async function verifyTagName(tagName) {
 /**
  * Verify the local branch is up to date with the remote one.
  *
- * @param {String} repositoryUrl The remote repository URL.
  * @param {String} branch The repository branch for which to verify status.
  *
  * @return {Boolean} `true` is the HEAD of the current local branch is the same as the HEAD of the remote branch, falsy otherwise.
  */
-async function isBranchUpToDate(repositoryUrl, branch) {
+async function isBranchUpToDate(branch) {
   try {
     return await isRefInHistory(
-      (await execa.stdout('git', ['ls-remote', '--heads', repositoryUrl, branch])).match(/^(\w+)?/)[1]
+      (await execa.stdout('git', ['ls-remote', '--heads', 'origin', branch])).match(/^(\w+)?/)[1]
     );
   } catch (err) {
     debug(err);