adding 1.15.2 to TOC

Author: Alex Terentiev

docs/spfx/release-1.15.2.md

@@ -23,7 +23,7 @@ npm install @microsoft/generator-sharepoint@latest --global
 ## Upgrading projects from v1.15.0 to v1.15.2
 
 1. In the project's **package.json** file, identify all SPFx v1.15.0 packages. For each SPFx package:
-    1. Uninstall the existing v1.14 package:
+    1. Uninstall the existing v1.15 package:
 
         ```console
         npm uninstall @microsoft/{spfx-package-name}@1.15.0

docs/toc.yml

@@ -458,6 +458,8 @@
     items:
     - name: Overview
       href: spfx/roadmap.md
+    - name: SPFx v1.15.2 - August 2, 2022
+      href: spfx/release-1.15.2.md      
     - name: SPFx v1.15 - June 21, 2022
       href: spfx/release-1.15.md      
     - name: SPFx v1.14 - February 17, 2022