Unpin test dependencies. (#196)

Author: carltongibson

.gitignore

@@ -5,3 +5,4 @@ build/
 *.pyc
 /.tox
 .DS_Store
+.pytest_cache

.travis.yml

@@ -11,6 +11,7 @@ services:
   - redis-server
 
 install:
+  - pip install -U pytest  # Travis comes with an old version pre-installed.
   - pip install -e .[tests]
   - pip freeze
 

setup.py

@@ -10,10 +10,10 @@
 crypto_requires = ["cryptography>=1.3.0"]
 
 test_requires = crypto_requires + [
-    "pytest~=5.4.0",
-    "pytest-asyncio~=0.8",
-    "async_generator~=1.8",
-    "async-timeout~=2.0",
+    "pytest",
+    "pytest-asyncio",
+    "async_generator",
+    "async-timeout",
 ]