apollo-parser@0.6.3

Fixes

• apply recursion limit where needed, reduce its default from 4096 to 500 - SimonSapin, pull/662
  The limit was only tracked for nested selection sets, but the parser turns out
  to use recursion in other cases too. Issue 666 tracks reducing them.
  Stack overflow was observed with little more than 2000
  nesting levels or repetitions in the new test.
  Defaulting to a quarter of that leaves a comfortable margin.
• fix various lexer bugs - SimonSapin, pull/646, pull/652
  The lexer was too permissive in emitting tokens instead of errors
  in various cases around numbers, strings, and EOF.
• fix panic on surrogate code points in unicode escape sequences - SimonSapin, issue/608, pull/658