[R2] Update durability.mdx

Per https://jira.cfdata.org/browse/SPM-2989

Author: nenizera

src/content/docs/r2/reference/durability.mdx

@@ -13,7 +13,7 @@ For example, if you store 1,000,000 objects on R2, you can expect to lose an obj
 :::caution
 
 
-Keep in mind that if you accidentally delete an object, you are responsible for implementing your own solution for backups.
+Keep in mind that if you accidentally delete an object, or an unauthorized party gains access to your R2 environment, you are responsible for implementing your own solution for backups.
 
 
 :::