Set version number to 6.2.0

Closes #3165

docs/releases/v6.2.0.rst

@@ -1,8 +1,8 @@
 What's new in Tornado 6.2.0
 ===========================
 
-Jun XX, 2022
-------------
+Jul 3, 2022
+-----------
 
 Deprecation notice
 ~~~~~~~~~~~~~~~~~~
@@ -75,6 +75,8 @@ General changes
   has been unnecessary since Python 3.2 added a logger of last resort.
 - The `.IOLoop` constructor now accepts an ``asyncio_loop`` keyword argument to
   initialize with a specfied asyncio event loop.
+- It is now possible to construct an `.IOLoop` on one thread (with
+  ``make_current=False``) and start it on a different thread.
 
 `tornado.iostream`
 ~~~~~~~~~~~~~~~~~~

tornado/__init__.py

@@ -22,5 +22,5 @@
 # is zero for an official release, positive for a development branch,
 # or negative for a release candidate or beta (after the base version
 # number has been incremented)
-version = "6.2b2"
-version_info = (6, 2, 0, -98)
+version = "6.2"
+version_info = (6, 2, 0, 0)