Use extras_require for tox deps

tox.ini

@@ -3,18 +3,12 @@ envlist = py38, py37, py36, py35, pypy3
 recreate = False
 
 [testenv]
+extras = tests
 setenv =
     PYLAST_USERNAME={env:PYLAST_USERNAME:}
     PYLAST_PASSWORD_HASH={env:PYLAST_PASSWORD_HASH:}
     PYLAST_API_KEY={env:PYLAST_API_KEY:}
     PYLAST_API_SECRET={env:PYLAST_API_SECRET:}
-deps =
-    pyyaml
-    pytest
-    ipdb
-    pytest-cov
-    pytest-random-order
-    flaky
 commands = pytest -v -s -W all --cov pylast --cov-report term-missing --random-order {posargs}
 
 [testenv:venv]