chore: version 0.8.0 and install pin

- package.json version 0.8.0, README install line #v0.8.0 (L4 CR-01)
- Upgrading from 0.7: the HTML sitemap pages, the catch-all rule and
  seo.htmlSitemap.overCatchAll (L4 WR-04), the post page's article meta
  and the path-form listing segments
- the link:../vue-seo-layer dependency stays until the release swap

package.json

@@ -1,6 +1,6 @@
 {
   "name": "vue-journal-layer",
-  "version": "0.7.1",
+  "version": "0.8.0",
   "private": true,
   "type": "module",
   "main": "./nuxt.config.ts",