build(deps): pin requests to <2.32.0

Version 2.32.0 breaks with the "http+unix" protocol used by requests-unixsocket,
which in turn is used by craft-parts. Pin this as a "dev" dependency since the
issue is in craft-parts, and not here.

Ref: msabramo/requests-unixsocket#73

pyproject.toml

@@ -54,6 +54,8 @@ dev = [
     "pytest-mock==3.14.0",
     "pytest-rerunfailures==14.0",
     "pytest-time>=0.3.1",
+    # Pin requests because of https://github.com/msabramo/requests-unixsocket/issues/73
+    "requests<2.32.0",
     "responses~=0.25.0",
     "craft-application[remote]"
 ]