upgrade facebook-business version

[aprvagrwl]

Make sure you have checked all steps below.

Issue

• Upgrade facebook-business package as FB would deprecate support for versions below v15.

Description

• changed the version of the image and upgraded the facebook-business==16.0.0

Tests

• My PR adds the following unit tests OR does not need testing for this extremely good reason:

Commits

• I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body explains "what" and "why", not "how"

Documentation

• In case of new functionality, my PR adds documentation that describes how to use it.
  • All the public functions and the classes in the PR contain docstrings that explain what it does