docs: fix migration guide link

Author: vkarpov15

docs/guide.md

@@ -1,7 +1,7 @@
 # Schemas
 
 If you haven't yet done so, please take a minute to read the [quickstart](index.html) to get an idea of how Mongoose works.
-If you are migrating from 6.x to 7.x please take a moment to read the [migration guide](migrating_to_7.html).
+If you are migrating from 7.x to 8.x please take a moment to read the [migration guide](migrating_to_8.html).
 
 <ul class="toc">
   <li><a href="#definition">Defining your schema</a></li>

docs/guides.md

@@ -50,6 +50,7 @@ integrating Mongoose with external tools and frameworks.
 
 ## Migration Guides
 
+* [Mongoose 7.x to 8.x](migrating_to_8.html)
 * [Mongoose 6.x to 7.x](migrating_to_7.html)
 * [Mongoose 5.x to 6.x](migrating_to_6.html)
 * [Mongoose 4.x to 5.x](migrating_to_5.html)

docs/layout.pug

@@ -133,7 +133,7 @@ html(lang='en')
                   li.pure-menu-item.sub-item
                     a.pure-menu-link(href=`${versions.versionedPath}/docs/api/virtualtype.html`, class=outputUrl === `${versions.versionedPath}/docs/api/virtualtype.html` ? 'selected' : '') VirtualType
               li.pure-menu-item
-                a.pure-menu-link(href=`${versions.versionedPath}/docs/migrating_to_7.html`, class=outputUrl === `${versions.versionedPath}/docs/migrating_to_7.html` ? 'selected' : '') Migration Guide
+                a.pure-menu-link(href=`${versions.versionedPath}/docs/migrating_to_8.html`, class=outputUrl === `${versions.versionedPath}/docs/migrating_to_8.html` ? 'selected' : '') Migration Guide
               li.pure-menu-item
                 a.pure-menu-link(href=`${versions.versionedPath}/docs/compatibility.html`, class=outputUrl === `${versions.versionedPath}/docs/compatibility.html` ? 'selected' : '') Version Compatibility
               li.pure-menu-item