We're at that time again where we want to make a new release.

For the v0.27 series, codenamed "Stadtrandsiedlung"

• Bump the versions in the headers
• Make a release candidate
• Plug any final leaks
• Fix any last-minute issues
• Make sure CHANGELOG reflects everything worth discussing
• Update the version in CHANGELOG and the header
• Produce a release candidate
• Tag
• Create maint/v0.27
• Update any bindings the core team works with

For v0.26.1

• Select the changes we want to backport
• Update maint/v0.26
• Tag