Update the regex used for searching for ETag's in gsutil's output

The ETag's for some of the crx files contain non alpha
and non digit characters like '='.

Bug:1225491
Bug:b/191630810
Change-Id: Id43ed8ea5fc17825731dd1605c7d6358ceed39cd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3287293Reviewed-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Rakib Hasan <rmhasan@google.com>

upload_to_google_storage.py

@@ -84,11 +84,11 @@ def _upload_worker(
     if gsutil.check_call('ls', file_url)[0] == 0 and not force:
       # File exists, check MD5 hash.
       _, out, _ = gsutil.check_call_with_retries('ls', '-L', file_url)
-      etag_match = re.search(r'ETag:\s+([a-z0-9]{32})', out)
+      etag_match = re.search(r'ETag:\s+\S+', out)
       if etag_match:
         stdout_queue.put(
             '%d> File with url %s already exists' % (thread_num, file_url))
-        remote_md5 = etag_match.group(1)
+        remote_md5 = etag_match.group(0).split()[1]
         # Calculate the MD5 checksum to match it to Google Storage's ETag.
         with md5_lock:
           if use_md5: