devel/py-botocore: Update to 1.12.142

• Update RUN_DEPENDS to match setup.py versions, document max versions
• Add TEST_DEPENDS and test target

Changelog:

https://github.com/boto/botocore/blob/1.12.142/CHANGELOG.rst

Reviewed by: bhughes
Approved by: bhughes (maintainer)
Differential Revision: D20161