0.2.3

CHANGES:

• Moved to Dune.
• Renders faster, uses less memory.
• Nested uses of I.pp_attr within I.strf now stack, instead of replacing.
• Removed dependency on Uucp. Uses internal data instead (Unicode 13).
• Support OCaml 4.08 - 4.14. Thanks to @kit-ty-kate for the 4.14 fixes.