Updates regex used to validate tagnames to allow for tagnames that include namespace information (esp: svg tags) (#77)

Co-authored-by: Mitch Goshorn <mitch.goshorn@calmid.com>

src/snapshot.ts

@@ -12,7 +12,7 @@ import {
 import { isElement, isShadowRoot } from './utils';
 
 let _id = 1;
-const tagNameRegex = RegExp('[^a-z0-9-_]');
+const tagNameRegex = RegExp('[^a-z0-9-_:]');
 
 export const IGNORED_NODE = -2;