[Feature request]: Add meta tags to be used in pages filter method

[staffordrose]

The document query is missing meta tags (Prismic tagging system).

Adding tags will allow them to be used as a filter in the plugin's pages filter method.

gatsby-source-prismic-graphql/packages/gatsby-source-prismic-graphql/src/gatsby-node.ts

Lines 184 to 195 in ad9d0d0

	_meta {
	id
	lang
	uid
	type
	alternateLanguages {
	id
	lang
	type
	uid
	}
	}

[bobsingor]

I need this feature.