Update mautrix-python

requirements.txt

@@ -1,8 +1,8 @@
 ruamel.yaml>=0.15.35,<0.17
 python-magic>=0.4,<0.5
 commonmark>=0.8,<0.10
-aiohttp>=3,<4
+aiohttp>=3,<3.7
 yarl>=1,<1.6
 attrs>=19.1
-mautrix==0.8.0b3
+mautrix==0.8.0.beta4
 asyncpg>=0.20,<0.22