Simplify update-authors.py

Before this change, there was effectively two for loops, one for the
list comprehension and one to iterate over the resulting list.
Generating the list wasn’t necessary since the code would just
immediately iterate over the list after it was generated, and then never
do anything with the list ever again.

update-authors.py

@@ -7,10 +7,9 @@
 
 git_log = subprocess.check_output(['git', 'shortlog', '--summary', '--email'])
 log_entries = git_log.decode('utf-8').strip().split('\n')
-authors = [author_re.search(entry).group(0) for entry in log_entries]
 
 
 print("Galaxy has been contribued to by the following authors:\n"
       "This list is automatically generated - please file an issue for corrections)\n")
-for author in authors:
-    print(author)
+for entry in log_entries:
+    print(author_re.search(entry).group(0))