Updating 1.15 release notes on the RC publishing

Author: VesaJuvonen

docs/spfx/release-1.15.md

@@ -1,7 +1,7 @@
 ---
 title: SharePoint Framework v1.15 preview release notes
 description: Release notes for the SharePoint Framework v1.15 preview release
-ms.date: 4/31/2022
+ms.date: 06/01/2022
 ms.prod: sharepoint
 ms.localizationpriority: high
 ---
@@ -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)]
 
-- rc.1 **Released:** May 31, 2022
+- rc.1 **Released:** June 1, 2022
 - beta.6 **Released:** April 19, 2022
 - beta.1 **Released:**  March 8, 2022