path regarding context entry

[Scrum]

posthtml:
			options:
				use: [
					require('posthtml-img-autosize')(
						root: 'byEntry'
					)
				]

or new property ctx

posthtml:
			options:
				use: [
					require('posthtml-img-autosize')(
						ctx: 'byEntry'
					)
				]

Originally posted by @Scrum in https://github.com/posthtml/posthtml-img-autosize/issues/17#issuecomment-712737665