bpo-33336, imaplib: Legalize MOVE command (GH-6569) (GH-8409)

imaplib now allows MOVE command in IMAP4.uid() (RFC 6851:
IMAP MOVE Extension) and potentially as a name of supported
method of IMAP4 object.
(cherry picked from commit caa331d492acc67d8f4edd16542cebfabbbe1e79)

Co-authored-by: Matěj Cepl <mcepl@cepl.eu>
diff --git a/Lib/imaplib.py b/Lib/imaplib.py
index e1cece0..0dfd852 100644
--- a/Lib/imaplib.py
+++ b/Lib/imaplib.py
@@ -79,6 +79,7 @@
         'LOGIN':        ('NONAUTH',),
         'LOGOUT':       ('NONAUTH', 'AUTH', 'SELECTED', 'LOGOUT'),
         'LSUB':         ('AUTH', 'SELECTED'),
+        'MOVE':         ('SELECTED',),
         'NAMESPACE':    ('AUTH', 'SELECTED'),
         'NOOP':         ('NONAUTH', 'AUTH', 'SELECTED', 'LOGOUT'),
         'PARTIAL':      ('SELECTED',),                                  # NB: obsolete