Updated v1.21 date in TOC

Author: VesaJuvonen

docs/toc.yml

@@ -474,7 +474,7 @@
     items:
     - name: Overview
       href: spfx/roadmap.md
-    - name: SPFx v1.21 - February 25, 2024
+    - name: SPFx v1.21 - April 3, 2024
       href: spfx/release-1.21.md        
     - name: SPFx v1.20 - September 26, 2024
       href: spfx/release-1.20.md