Merge pull request #834 from screamerbg/f/tags_git_2_20

Fix: Add --force flag to `git fetch` to allow tags to be fetched in git 2.20

Author: theotherjimmy

mbed/mbed.py

@@ -753,7 +753,7 @@ def publish(all_refs=None):
 
     def fetch():
         info("Fetching revisions from remote repository to \"%s\"" % os.path.basename(getcwd()))
-        popen([git_cmd, 'fetch', '--all', '--tags'] + (['-v'] if very_verbose else ([] if verbose else ['-q'])))
+        popen([git_cmd, 'fetch', '--all', '--tags', '--force'] + (['-v'] if very_verbose else ([] if verbose else ['-q'])))
 
     def discard(clean_files=False):
         info("Discarding local changes in \"%s\"" % os.path.basename(getcwd()))