Update README.md

Author: jshackell-sfdc

releasenotes/README.md

@@ -25,7 +25,7 @@ Additional documentation:
 * [Salesforce CLI Plugin Developer Guide](https://github.com/salesforcecli/cli/wiki/Quick-Introduction-to-Developing-sf-Plugins)
 * [Salesforce CLI Setup Guide](https://developer.salesforce.com/docs/atlas.en-us.sfdx_setup.meta/sfdx_setup/sfdx_setup_intro.htm)
 
-## 2.78.5 (Feb 26, 2025) [stable-rc]
+## 2.78.3 (Feb 26, 2025) [stable-rc]
 
 These changes are in the Salesforce CLI release candidate. We plan to include these changes in next week's official release. This list isn't final and is subject to change.