Fails to install with pip 8.1.1

**Describe the bug**

A minor issue, since it only happens with very old pip versions, but datadogpy fails to install because configparser>=5 is not compatible with any python2. [Their documentation ](https://github.com/jaraco/configparser/blob/master/CHANGES.rst#v500) says "this should be automatic with pip 9" but there's no harm in being explicit and adding compatibility for older versions. I h



**To Reproduce**

pip install --upgrade pip==8.1.1

pip install datadog



**Expected behavior**

datadogpy installs successfully 



**Actual behavior**

```

Collecting datadog

  Using cached https://files.pythonhosted.org/packages/53/a2/44813679fbb1f3203b2b2aba35a01123da6e32d6f09fbe503f781b8c2fcb/datadog-0.37.1-py2.py3-none-any.whl

Collecting requests>=2.6.0 (from datadog)

  Using cached https://files.pythonhosted.org/packages/45/1e/0c169c6a5381e241ba7404532c16a21d86ab872c9bed8bdcd4c423954103/requests-2.24.0-py2.py3-none-any.whl

Collecting decorator>=3.3.2 (from datadog)

  Using cached https://files.pythonhosted.org/packages/ed/1b/72a1821152d07cf1d8b6fce298aeb06a7eb90f4d6d41acec9861e7cc6df0/decorator-4.4.2-py2.py3-none-any.whl

Collecting configparser; python_version < "3.0" (from datadog)

Collecting typing; python_version < "3.5" (from datadog)

  Using cached https://files.pythonhosted.org/packages/22/30/64ca29543375759dc589ade14a6cd36382abf2bec17d67de8481bc9814d7/typing-3.7.4.1-py2-none-any.whl

Collecting chardet<4,>=3.0.2 (from requests>=2.6.0->datadog)

  Using cached https://files.pythonhosted.org/packages/bc/a9/01ffebfb562e4274b6487b4bb1ddec7ca55ec7510b22e4c51f14098443b8/chardet-3.0.4-py2.py3-none-any.whl

Collecting urllib3!=1.25.0,!=1.25.1,<1.26,>=1.21.1 (from requests>=2.6.0->datadog)

  Using cached https://files.pythonhosted.org/packages/e1/e5/df302e8017440f111c11cc41a6b432838672f5a70aa29227bf58149dc72f/urllib3-1.25.9-py2.py3-none-any.whl

Collecting idna<3,>=2.5 (from requests>=2.6.0->datadog)

  Using cached https://files.pythonhosted.org/packages/a2/38/928ddce2273eaa564f6f50de919327bf3a00f091b5baba8dfa9460f3a8a8/idna-2.10-py2.py3-none-any.whl

Collecting certifi>=2017.4.17 (from requests>=2.6.0->datadog)

  Using cached https://files.pythonhosted.org/packages/5e/c4/6c4fe722df5343c33226f0b4e0bb042e4dc13483228b4718baf286f86d87/certifi-2020.6.20-py2.py3-none-any.whl

Installing collected packages: chardet, urllib3, idna, certifi, requests, decorator, configparser, typing, datadog

Exception:

Traceback (most recent call last):

  File "/usr/lib/python2.7/dist-packages/pip/basecommand.py", line 209, in main

    status = self.run(options, args)

  File "/usr/lib/python2.7/dist-packages/pip/commands/install.py", line 335, in run

    prefix=options.prefix_path,

  File "/usr/lib/python2.7/dist-packages/pip/req/req_set.py", line 732, in install

    **kwargs

  File "/usr/lib/python2.7/dist-packages/pip/req/req_install.py", line 837, in install

    self.move_wheel_files(self.source_dir, root=root, prefix=prefix)

  File "/usr/lib/python2.7/dist-packages/pip/req/req_install.py", line 1039, in move_wheel_files

    isolated=self.isolated,

  File "/usr/lib/python2.7/dist-packages/pip/wheel.py", line 346, in move_wheel_files

    assert info_dir, "%s .dist-info directory not found" % req

AssertionError: configparser; python_version < "3.0" .dist-info directory not found

You are using pip version 8.1.1, however version 20.1.1 is available.

You should consider upgrading via the 'pip install --upgrade pip' command.

```

**Environment and Versions (please complete the following information):**

datadogpy version 0.37.1 being installed through an ansible task on an Ubuntu 16.04 AWS EC2 machine. Though the issue was also replicable calling pip directly instead of through ansible.



**Additional context**

N/A

[]