Merge branch 'develop' into rav/fix_attribute_mapping

.buildkite/docker-compose.py35.pg95.yaml

.buildkite/docker-compose.py37.pg11.yaml

.buildkite/docker-compose.py37.pg95.yaml

.buildkite/format_tap.py

.buildkite/merge_base_branch.sh

.buildkite/pipeline.yml

.coveragerc

.gitignore

CONTRIBUTING.rst

INSTALL.md

MANIFEST.in

README.rst

UPGRADE.rst

changelog.d/5633.bugfix

changelog.d/5680.misc

changelog.d/5771.feature

changelog.d/5776.misc

changelog.d/5835.feature

changelog.d/5844.misc

changelog.d/5845.feature