gnu: Add python-async-timeout.

* gnu/packages/python.scm (python-async-timeout): New variable.

gnu/packages/python.scm

@@ -13238,3 +13238,20 @@ generators and Python 3.7's context managers into Python 3.5.")
     ;; Dual licensed.
     (license (list license:expat license:asl2.0))))
 
+(define-public python-async-timeout
+  (package
+    (name "python-async-timeout")
+    (version "2.0.1")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (pypi-uri "async-timeout" version))
+       (sha256
+        (base32
+         "1l3kg062m02mph6rf9rdv8r5c5n356clxa6b6mrn0i77vk9g9kq0"))))
+    (build-system python-build-system)
+    (home-page "https://github.com/aio-libs/async_timeout/")
+    (synopsis "Timeout context manager for asyncio programs")
+    (description "@code{async-timeout} provides a timeout timeout context
+manager compatible with @code{asyncio}.")
+    (license license:asl2.0)))