USN-6155-2: Requests vulnerability

USN-6155-2: Requests vulnerability

USN-6155-1 fixed a vulnerability in Requests. This update provides
the corresponding update for Ubuntu 16.04 ESM and 18.04 ESM.

Original advisory details:

Dennis Brinkrolf and Tobias Funke discovered that Requests incorrectly
leaked Proxy-Authorization headers. A remote attacker could possibly use
this issue to obtain sensitive information.
Source: USN-6155-2: Requests vulnerability