Emacs 27.1 was released nearly 6 years ago (August 2020). Bumping
the minimum version lets us remove ~30 lines of compatibility code:
- Remove fileloop fallback using deprecated tags-loop-scan/operate
- Fix tags-query-replace FIXME in projectile-replace-regexp by using
fileloop-initialize-replace + fileloop-continue
- Replace projectile-flatten with built-in flatten-tree (6 call sites)
- Simplify projectile-time-seconds to just (time-convert nil 'integer)
- Use proper-list-p for known-projects file validation
- Use json-parse-buffer unconditionally in CMake preset reader
- Use package-get-version unconditionally
- Add (require 'fileloop) as a proper dependency
- Drop Emacs 26.3 from CI matrix