fix(git): wrong fetch args (#3663)

lib/platform/git/storage.js

@@ -85,7 +85,10 @@ class Storage {
           git = Git(cwd).silent(true);
           await git.raw(['remote', 'set-url', 'origin', config.url]);
           const fetchStart = process.hrtime();
-          await git.fetch(config.url, ['--depth=2', '--no-single-branch']);
+          await git.fetch(config.url, {
+            '--depth': '2',
+            '--no-single-branch': true,
+          });
           await determineBaseBranch();
           await resetToBranch(config.baseBranch);
           await cleanLocalBranches();