Add httpx recipe (#3100)

* add httpx recipe

* flake8 fix

Author: DexerBR

pythonforandroid/recipes/httpx/__init__.py

@@ -0,0 +1,13 @@
+from pythonforandroid.recipe import PyProjectRecipe
+
+
+class HttpxRecipe(PyProjectRecipe):
+    name = "httpx"
+    version = "0.28.1"
+    url = (
+        "https://pypi.python.org/packages/source/h/httpx/httpx-{version}.tar.gz"
+    )
+    depends = ["httpcore", "h11", "certifi", "idna", "sniffio"]
+
+
+recipe = HttpxRecipe()