py-memcached: updated to 1.61

1.61

* Fixing the ChangeLog entry which had a bad date.

1.60

*  Allow to use a datetime.timedelta parameter for Client.set
*  Fix cmemcahe_hash 0 values being translated to 1
*  Fix tuple key support in multi methods
*  Add support for default value in get
*  test_memcache.py: try import unittest.mock
*  Use == as suggested by Python 3.8
*  Decoding in slab funcs, replacing "1" with "True" in while.
*  Tell PyPI to parse README as markdown
*  test_memcache.py: try import unittest.mock
*  Removed Python 2.7 from setup.cfg, adding 3.8-3.12
*  Add support for default value in get()
*  Fix tuple key support in multi methods (regression in 1.55).
*  Fix cmemcahe_hash 0 values being translated to 1.  For example "ob"
   would hash to 0 and then get converted to 1.  Looks like this dated
   back to 2009, the original code we imported for that hash function.
*  Removing six.PY2/3 conditionals
*  Removing "time" from delete and making expiry mandatory in touch.
*  Added quit() method.  This method sends the 'quit' command to the
   servers and then closes the connections, reducing the number of
   TIME_WAIT sockets hanging around the OS.
*  Allow to use a datetime.timedelta parameter for Client.set
*  Allow keys to be encoded before use.
*  Removing historic python 2to3 code and deprecated socket.error (for
   OSError).
*  Updating to the latest PSF license


(adam)