Add option to use new Virtual Templates feature to avoid creating feed template files manually.

[zachleat]

The docs right now require both addPlugin and creation of a file on your file system to populate your feed. We can simplify this to one step with virtual templates: 11ty/eleventy#1612

https://www.11ty.dev/docs/plugins/rss/#sample-feed-templates

Related: #38 and 11ty/eleventy#3294

[zachleat]

Usage example for RSS Plugin v2.0:

import { feedPlugin } from "@11ty/eleventy-plugin-rss";

export default function(eleventyConfig) {
	eleventyConfig.addPlugin(feedPlugin, {
		type: "atom", // "json" or "rss" also supported.
		outputPath: "/feed/feed.xml",
		collection: {
			name: "posts",
			limit: 10,
		},
		metadata: {
			language: "en",
			title: "Blog Title",
			subtitle: "This is a longer description about your blog.",
			base: "https://example.com/",
			author: {
				name: "Your Name",
				email: "me@example.com"
			}
		}
	});
};

[zachleat]

Finalizing this one, it’ll be ready with Eleventy core v3.0.0-alpha.13. Ironed out one last bug today with absolute URL transformation.

[zachleat]

Docs are live on https://www.11ty.dev/docs/plugins/rss/#virtual-template