Remove pinned dependency on yarl==1.9.2

yarl 1.9.2 provides wheels only for Python versions up to 3.11, making
Wavelink installation on Python 3.12 harder than it should be on setups
without build deps.

Changing the requirement to `yarl>=1.9.2` fixes this

requirements.txt

@@ -1,4 +1,4 @@
 aiohttp>=3.7.4,<4
 discord.py>=2.0.1
-yarl==1.9.2
+yarl>=1.9.2
 async_timeout