Merge branch 'develop' into cross-signing_sig_upload

.github/ISSUE_TEMPLATE/BUG_REPORT.md

.gitignore

CHANGES.md

CONTRIBUTING.rst

INSTALL.md

MANIFEST.in

README.rst

UPGRADE.rst

changelog.d/1172.misc

changelog.d/2142.feature

changelog.d/2380.bugfix

changelog.d/3436.bugfix

changelog.d/4088.bugfix

changelog.d/5633.bugfix

changelog.d/5680.misc

changelog.d/5759.misc

changelog.d/5771.feature

changelog.d/5776.misc

changelog.d/5835.feature

changelog.d/5844.misc