(v2) chore(requirements): drop unused dependencies (#2060)

These were lifted from the v3 branch wholesale, but are not actually in
use in v2.

Changes proposed in this pull request:

 - drop a2wsgi, httpx, uvicorn, typing-extensions direct dependencies
 - typing-extensions still exists as a transitive dependency

Author: noirbee

.gitignore

@@ -16,3 +16,4 @@ venv/
 .venv/
 src/
 *.un~
+poetry.lock