Add async-timeout to dependencies

For some reason, async-timeout needs to be specifically marked as >=4
when using the aiohttp package.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

Pipfile

@@ -8,6 +8,7 @@ async-irc = "*"
 toml = {version="*", markers="python_version < '3.11'"}
 types-toml = "*"
 "aiohttp[speedups]" = "*"
+async-timeout = ">=4"
 
 [dev-packages]
 mypy = "*"