Added httpx to fastapi test requirements

tox.ini

@@ -116,15 +116,13 @@ deps =
     django-{1.11,2.0,2.1,2.2,3.0,3.1,3.2}: djangorestframework>=3.0.0,<4.0.0
 
     {py3.7,py3.8,py3.9,py3.10}-django-{1.11,2.0,2.1,2.2,3.0,3.1,3.2}: channels[daphne]>2
-    {py3.7,py3.8,py3.9,py3.10}-django-{1.11,2.0,2.1,2.2,3.0,3.1,3.2}: pytest-asyncio
     {py2.7,py3.7,py3.8,py3.9,py3.10}-django-{1.11,2.2,3.0,3.1,3.2}: psycopg2-binary
 
     django-{1.8,1.9,1.10,1.11,2.0,2.1}: pytest-django<4.0
     django-{2.2,3.0,3.1,3.2}: pytest-django>=4.0
     django-{2.2,3.0,3.1,3.2}: Werkzeug<2.0
 
     django-{4.0,4.1}: djangorestframework
-    django-{4.0,4.1}: pytest-asyncio
     django-{4.0,4.1}: psycopg2-binary
     django-{4.0,4.1}: pytest-django
     django-{4.0,4.1}: Werkzeug
@@ -149,14 +147,11 @@ deps =
     flask-1.1: Flask>=1.1,<1.2
     flask-2.0: Flask>=2.0,<2.1
 
-    asgi: pytest-asyncio
     asgi: async-asgi-testclient
 
     quart: quart>=0.16.1
     quart: quart-auth
-    quart: pytest-asyncio
 
-    starlette: pytest-asyncio
     starlette: python-multipart
     starlette: requests
     starlette-0.21: httpx
@@ -165,7 +160,7 @@ deps =
     starlette-0.21: starlette>=0.21.0,<0.22.0
 
     fastapi: fastapi
-    fastapi: pytest-asyncio
+    fastapi: httpx
     fastapi: python-multipart
     fastapi: requests