Fix CVE-2018-1060:
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-1060

Taken from upstream commit (sans test and NEWS):
https://github.com/python/cpython/commit/e052d40cea15f582b50947f7d906b39744dc62a2

diff --git a/Lib/poplib.py b/Lib/poplib.py
index b91e5f72d2ca..a238510b38fc 100644
--- a/Lib/poplib.py
+++ b/Lib/poplib.py
@@ -274,7 +274,7 @@ def rpop(self, user):
         return self._shortcmd('RPOP %s' % user)
 
 
-    timestamp = re.compile(r'\+OK.*(<[^>]+>)')
+    timestamp = re.compile(br'\+OK.[^<]*(<.*>)')
 
     def apop(self, user, secret):
         """Authorisation

put type='hidden' name='id' value='5ed42eb9a01e63c25d6c0836b6a1b15e8d5fbd74'/><select name='h' onchange='this.form.submit();'>
<option value='koszko' selected='selected'>koszko</option>
<option value='koszko-scripts'>koszko-scripts</option>
</select> <input type='submit' value='switch'/></form></td></tr>
<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
<table class='tabs'><tr><td>
<a href='/guix/about/'>about</a><a href='/guix/'>summary</a><a href='/guix/refs/?id=5ed42eb9a01e63c25d6c0836b6a1b15e8d5fbd74'>refs</a><a class='active' href='/guix/log/po/packages/nl.po'>log</a><a href='/guix/tree/po/packages/nl.po?id=5ed42eb9a01e63c25d6c0836b6a1b15e8d5fbd74'>tree</a><a href='/guix/commit/po/packages/nl.po?id=5ed42eb9a01e63c25d6c0836b6a1b15e8d5fbd74'>commit</a><a href='/guix/diff/po/packages/nl.po?id=5ed42eb9a01e63c25d6c0836b6a1b15e8d5fbd74'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/po/packages/nl.po'>
<input type='hidden' name='id' value='5ed42eb9a01e63c25d6c0836b6a1b15e8d5fbd74'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=5ed42eb9a01e63c25d6c0836b6a1b15e8d5fbd74'>root</a>/<a href='/guix/log/po?id=5ed42eb9a01e63c25d6c0836b6a1b15e8d5fbd74'>po</a>/<a href='/guix/log/po/packages?id=5ed42eb9a01e63c25d6c0836b6a1b15e8d5fbd74'>packages</a>/<a href='/guix/log/po/packages/nl.po?id=5ed42eb9a01e63c25d6c0836b6a1b15e8d5fbd74'>nl.po</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/po/packages/nl.po?id=5ed42eb9a01e63c25d6c0836b6a1b15e8d5fbd74&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-09-02 04:06:52 +0200'>2021-09-02</span></td><td><a href='/guix/commit/po/packages/nl.po?id=1ff2092a39dc5c7c7cd9b4a0ba4b59f92e738efc'>nls: Update translations.</a><span class='msg-avail'>...<span class='msg-tooltip'>* po/packages/it.po: New file.
* po/packages/LINGUAS: Add `it'.
* po/*/*.po: Update translations.
</span></span></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2021-08-04 14:49:53 +0200'>2021-08-04</span></td><td><a href='/guix/commit/po/packages/nl.po?id=6c10c96fedf707d7be059aeb79bd5c8e2d2fa210'>nls: Update translations.</a><span class='msg-avail'>...<span class='msg-tooltip'>* po/doc/guix-cookbook.ru.po: New file.
* po/doc/guix-cookbook.sk.po: New file.
* po/*/*.po: Update translations.
* doc/local.mk (COOKBOOK_LANGUAGES): Add ru and sk.
(info_TEXINFOS): Add Russian and Slovak cookbooks.
* po/doc/local.mk (DOC_COOKBOOK_PO_FILES): Add Russian and Slovak po
files.
</span></span></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2021-05-10 22:27:53 -0400'>2021-05-10</span></td><td><a href='/guix/commit/po/packages/nl.po?id=63d26e81eea7be63caeb0eb7ca26ca1cf963ec97'>nls: New nl and oc translations for the 'packages' component.</a><span class='msg-avail'>...<span class='msg-tooltip'>* po/packages/nl.po: New file.
* po/packages/oc.po: Likewise.
* po/packages/LINGUAS: Register them.
</span></span></td><td>Maxim Cournoyer</td></tr>