v1.0.3 — support php-ron ^0.4 and ^0.5

Changed

• Allow mbolli/php-ron ^0.4 and ^0.5 alongside ^0.3. The Ron::tokenize() API and the
  RonToken/RonTokenKind shapes are unchanged across all three, so this is a constraint
  widening rather than a behaviour change — and the range means a future php-ron 0.x no longer
  needs a release here just to unblock consumers.

Fixed

• Highlighting of php-ron 0.5 sources. Its tokenizer treats a JSON escape as one scanner atom
  and classifies before decoding, so a\nb and ,foo each stay a single string span and
  tr\u0075e highlights as a string rather than the boolean literal. Covered by a new test.