Updating 1.15 preview release notes and adding to TOC

Author: VesaJuvonen

docs/spfx/release-1.15.md

@@ -11,7 +11,7 @@ There will be multiple public preview release using the @next tag in the NPMJS.o
 
 [!INCLUDE [spfx-release-beta](../../includes/snippets/spfx-release-beta.md)]
 
-**beta.1:** March 3, 2022
+**beta.1:** March 8, 2022
 
 [!INCLUDE [spfx-release-notes-common](../../includes/snippets/spfx-release-notes-common.md)]
 
@@ -57,10 +57,6 @@ this.context.msGraphClientFactory.getClient('3');
 
 The template was updated to use `listViewStateChanged` event instead of deprecated `onListViewUpdated` event.
 
-### Node 16 LTS
-
-- Node engines updated in package.json files to include Node 16 LTS `>=12.13.0 <13.0.0 || >=14.15.0 <15.0.0 || >=16.13.0 <17.0.0`.
-
 ## Deprecations
 
 - Deprecated SPComponentLoader#getManifests due to runtime performance overhead.

docs/toc.yml

@@ -456,6 +456,8 @@
     items:
     - name: Overview
       href: spfx/roadmap.md
+    - name: SPFx v1.14 - March 8, 2022
+      href: spfx/release-1.15.md      
     - name: SPFx v1.14 - February 17, 2022
       href: spfx/release-1.14.md
     - name: SPFx v1.13.1 - November 23, 2021