Adjust dependency version specifier

Author: singingwolfboy

requirements.txt

@@ -1,2 +1,2 @@
 requests>=2.0.0
-oauthlib[signedtoken]>=2.1.0,<3.0.0
+oauthlib[signedtoken]>=3.0.0

setup.py

@@ -44,8 +44,8 @@ def readall(path):
     url='https://github.com/requests/requests-oauthlib',
     packages=['requests_oauthlib', 'requests_oauthlib.compliance_fixes'],
     python_requires=">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*",
-    install_requires=['oauthlib>=2.1.0,<3.0.0', 'requests>=2.0.0'],
-    extras_require={'rsa': ['oauthlib[signedtoken]>=2.1.0,<3.0.0']},
+    install_requires=['oauthlib>=3.0.0', 'requests>=2.0.0'],
+    extras_require={'rsa': ['oauthlib[signedtoken]>=3.0.0']},
     license='ISC',
     classifiers=[
         'Development Status :: 5 - Production/Stable',