4.0.0

Two correctness fixes for isSupported(). Both change the boolean returned in
some cases, hence the major bump.

The public API itself is unchanged.

• Fixed: features flagged with a caniuse note are no longer reported as
  unsupported. caniuse stores full support as y, sometimes followed by a note
  (y #2) or a flag (y x); we now only check the leading support indicator
  instead of matching the whole value.
  (#82
  via #90
  by @underbyte)
  • e.g. isSupported("es6", "chrome 74") now returns true (was false).
• Fixed: an unknown browser version is now reported as unsupported instead of
  supported. A query resolving to no known browser (e.g. safari 12.0.2)
  previously returned true because of a vacuously-true [].every(…); it now
  returns false. (#83
  via #90
  by @underbyte)
  • e.g. isSupported("intersectionobserver", "safari 12.0.2") now returns
    false (was true).
  • isSupported still throws on a malformed query ("not a real browser")
    and on an unknown feature name, as before.
• Added: built-in TypeScript type declarations. The package is now written in
  TypeScript and ships its own .d.ts, so @types/caniuse-api is no longer
  needed.
  By @MoOx.
• Changed: internal rewrite, no runtime behaviour change. The previous build
  step was replaced by tsc (sources run natively under modern Node and are
  compiled to CommonJS for publishing), and the lodash.memoize / lodash.uniq
  dependencies were inlined — two fewer runtime dependencies.
  By @MoOx.

Note for tooling authors (e.g. cssnano / postcss-merge-rules): more features
are now considered supported than before, which can change generated output.
The new behaviour matches caniuse.com (dark green = supported).