Bump trio and downgrade attrs on the requirements.txt (#2660)

* Bump trio

* Downgrade attrs

Author: Kludex

requirements.txt

@@ -1,9 +1,6 @@
 # Optionals
 -e .[full]
 
-# TODO: We need to delete the following line when fixing the test suite for anyio 4.4.0.
-anyio==4.4.0
-
 # Testing
 coverage==7.6.0
 importlib-metadata==8.2.0
@@ -14,7 +11,9 @@ types-contextvars==2.4.7.3
 types-PyYAML==6.0.12.20240724
 types-dataclasses==0.6.6
 pytest==8.3.2
-trio==0.26.0
+trio==0.26.1
+# TODO: Remove when trio is updated.
+attrs==23.2.0
 
 # Documentation
 mkdocs==1.6.0