`Decompressor` uses inexistent dictionary API

[illia-v]

While I was working on #207, I noticed that the decompressor class allows passing a custom dictionary, but the functionality is not working because lib.BrotliDecoderSetCustomDictionary was dropped since v1.0.9.0.

brotlicffi/src/brotlicffi/_api.py

Lines 369 to 376 in 75ac969

	if dictionary:
	self._dictionary = ffi.new("uint8_t []", dictionary)
	self._dictionary_size = len(dictionary)
	lib.BrotliDecoderSetCustomDictionary(
	self._decoder,
	self._dictionary_size,
	self._dictionary
	)

AttributeError: cffi library '_brotlicffi' has no function, constant or global variable named 'BrotliDecoderSetCustomDictionary'. Did you mean: 'BrotliDecoderAttachDictionary'?

It may be possible to use BrotliDecoderAttachDictionary instead of BrotliDecoderSetCustomDictionary.

This functionality has been broken for a few releases, so I hope it doesn't block releasing v1.2.0.0.

[sethmlarson]

Good catch, this also signals to me that this feature is indeed used by almost no-one. If anyone submits a PR and I can make a 1.2.0.1 release.