Change WCAG 2.0 to WCAG 2 - Understanding Conformance

There are many references to WCAG 2.0 on the [updated Understanding Conformance page](https://www.w3.org/WAI/WCAG21/Understanding/conformance).

Should it not be change to a more generic term "WCAG 2" to include WCAG 2.1 and the yet to come WCAG 2.2?