* Add tools/merge_requirements.py
* Revert "Fix oldest tests by pinning Google DNS deps (#5000)"
This reverts commit f68fba2be2.
* Add tools/oldest_constraints.txt
* Remove oldest constraints from tox.ini
* Rename dev constraints file
* Update tools/pip_install.sh
* Update install_and_test.sh
* Fix pip_install.sh
* Don't cat when you can cp
* Add ng-httpsclient to dev constraints for oldest tests
* Bump tested setuptools version
* Update dev_constraints comment
* Better document oldest dependencies
* test against oldest versions we say we require
* Update dev constraints
* Properly handle empty lines
* Update constraints gen in pip_install
* Remove duplicated zope.component
* Reduce pyasn1-modules dependency
* Remove blank line
* pin back google-api-python-client
* pin back uritemplate
* pin josepy for oldest tests
* Undo changes to install_and_test.sh
* Update install_and_test.sh description
* use split instead of partition
