[tests] Remove tests_install and replace with tox configuration

setup.py

@@ -24,10 +24,7 @@ setup(
         'pynacl',
         'python-multipart',
         'pytoml',
+        'requests',
         'scrypt',
     ],
-    tests_require=[
-        'flake8',
-        'pytest',
-    ],
 )

tox.ini

@@ -0,0 +1,18 @@
+[tox]
+envlist = py38, flake8, pytest
+
+[testenv]
+deps = .
+
+[testenv:flake8]
+deps = flake8
+exclude = .tox
+commands = 
+     flake8 kibicara tests --count --select=E9,F63,F7,F82 --show-source --statistics
+     flake8 kibicara tests --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+
+[testenv:pytest]
+deps = pytest
+commands =
+     pytest
+