Bump path-to-regexp, major changes

[frenzzy]

• Update path-to-regexp to v2.0.0, see changelog (BREAKING CHANGE)
  • Explicitly handle trailing delimiters (e.g. /test/ is now treated as /test/ instead of /test when matching)
  • No wildcard asterisk (*) - use parameters instead ((.*))
• Add encode option to generateUrls(router, options) function for pretty encoding
  (e.g. pass your own implementation)

  import UniversalRouter from 'universal-router';
  import generateUrls from 'universal-router/generateUrls';
  
  const router = new UniversalRouter([
    { name: 'home', path: '/', },
    { name: 'user', path: '/user/:username' },
  ]);
  
  const url = generateUrls(router); // uses encodeURIComponent by default
  const prettyUrl = generateUrls(router, { encode: x => x });
  
  url('user', { username: ':/' });       // => '/user/%3A%2F'
  prettyUrl('user', { username: ':/' }); // => '/user/:/'

• Remove pretty option from generateUrls(router, options) function in favor of new encode option
• Preserve context.keys values from the parent route
• Inherit context.params and queryParams from Object (e.g. params.hasOwnProperty() won't throw an exception anymore), fixes Replace "params = Object.create(null)" with "params = {}" #106

[coveralls]

Coverage remained the same at 100.0% when pulling 65d3613 on frenzzy:path-to-regexp-v2 into 7883e10 on kriasoft:master.