drop support for Falcon 2

[yedpodtrzitko]

moreless copy-paste of my comment here: #225 (comment)

Falcon 2 was released 2019 and never got any patch above 2.0.0 (see https://pypi.org/project/falcon/#history ), so it seems unsupported anyway.

The reason why I would propse doing this is that Falcon 2 does not support form data. The pipeline in #225 fails right now because get_media() does not exist in Falcon 2, so I tried to use req.media instead, and I got the following error (with Falcon 2)

AssertionError: {"title": "Unsupported media type", "description": "multipart/form-data is an unsupported media type."}

Dropping Falcon 2 would then make implementing the form data support easier.

[kemingy]

Also, can you help to change the falcon demo in README?

Another thing related to falcon 2 is the

spectree/spectree/plugins/falcon_plugin.py

Lines 61 to 64 in 278f1bd

	# used to detect falcon 3.0 request media parse error
	self.FALCON_HTTP_ERROR = HTTPError
	self.FALCON_MEDIA_ERROR_CODE = (HTTP_400, HTTP_415)
	self.FIELD_PATTERN = _FIELD_PATTERN

• It's related to fix falcon3 media exception #174

[yedpodtrzitko]

it's rebased now, pipeline passing