Updated requirements, using pipenv

Pipfile

@@ -0,0 +1,12 @@
+[[source]]
+name = "pypi"
+url = "https://pypi.org/simple"
+verify_ssl = true
+
+[dev-packages]
+
+[packages]
+requests = "*"
+
+[requires]
+python_version = "2.7"

Pipfile.lock

@@ -0,0 +1,55 @@
+{
+    "_meta": {
+        "hash": {
+            "sha256": "9838c8bf3aa442453b393e09e534ba7e1666aab4da1b9b408ecdf3ae58ab273c"
+        },
+        "pipfile-spec": 6,
+        "requires": {
+            "python_version": "2.7"
+        },
+        "sources": [
+            {
+                "name": "pypi",
+                "url": "https://pypi.org/simple",
+                "verify_ssl": true
+            }
+        ]
+    },
+    "default": {
+        "certifi": {
+            "hashes": [
+                "sha256:993f830721089fef441cdfeb4b2c8c9df86f0c63239f06bd025a76a7daddb033"
+            ],
+            "version": "==2018.11.29"
+        },
+        "chardet": {
+            "hashes": [
+                "sha256:84ab92ed1c4d4f16916e05906b6b75a6c0fb5db821cc65e70cbd64a3e2a5eaae",
+                "sha256:fc323ffcaeaed0e0a02bf4d117757b98aed530d9ed4531e3e15460124c106691"
+            ],
+            "version": "==3.0.4"
+        },
+        "idna": {
+            "hashes": [
+                "sha256:156a6814fb5ac1fc6850fb002e0852d56c0c8d2531923a51032d1b70760e186e",
+                "sha256:684a38a6f903c1d71d6d5fac066b58d7768af4de2b832e426ec79c30daa94a16"
+            ],
+            "version": "==2.7"
+        },
+        "requests": {
+            "hashes": [
+                "sha256:65b3a120e4329e33c9889db89c80976c5272f56ea92d3e74da8a463992e3ff54",
+                "sha256:ea881206e59f41dbd0bd445437d792e43906703fff75ca8ff43ccdb11f33f263"
+            ],
+            "index": "pypi",
+            "version": "==2.20.1"
+        },
+        "urllib3": {
+            "hashes": [
+                "sha256:61bf29cada3fc2fbefad4fdf059ea4bd1b4a86d2b6d15e1c7c0b582b9752fe39"
+            ],
+            "version": "==1.24.1"
+        }
+    },
+    "develop": {}
+}

requirements.txt

@@ -1 +0,0 @@
-requests==2.11.1

setup.py

@@ -5,7 +5,7 @@ from setuptools import setup
 import os
 import sys
 
-version = '0.2.0'
+version = '0.3.0'
 
 if sys.argv[-1] == 'publish':
     os.system("python setup.py sdist upload")
@@ -27,7 +27,9 @@ setup(
     py_modules=['yubikey'],
     include_package_data=True,
     zip_safe=False,
-    install_requires=open('requirements.txt').read().split('\n'),
+    install_requires=[
+        "requests==2.20.1",
+    ],
     classifiers=[
         'Development Status :: 3 - Alpha',
         'Intended Audience :: Developers',