Update upgrade-to-1.3.10.mdx (#12341)

The upgrade guide indicates the upgrade path between two identical versions (1.3.10). Presumably you meant compared to 1.3.9?

Author: sebastien-rosset

website/content/docs/upgrading/upgrade-to-1.3.10.mdx

@@ -9,6 +9,6 @@ description: |-
 # Overview
 
 This page contains the list of deprecations and important or breaking changes
-for Vault 1.3.10 compared to 1.3.10. Please read it carefully.
+for Vault 1.3.10 compared to 1.3.9. Please read it carefully.
 
 @include 'aws-invalid-header-fix.mdx'