implement requests.Response context manager to use in with statement

[rgl]

In MicroPython 1.27.0 we can make a HTTP request like:

import requests
r = requests.get("http://ip6.me/api/", timeout=15)
print(r.text)
r.close()

Unfortunately, we cannot simplify that code to use the with statement:

with requests.get("http://ip6.me/api/", timeout=15) as r:
  print(r.text)

Because it fails with:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'Response' object has no attribute '__exit__'

Can that be implemented?

PS: Oh there is a PR at #278 that seems to implement this.