fix: correct property name from 'provider' to 'scanner' in README (#6)

Author: aykhanhuseyn

README.md

@@ -24,7 +24,7 @@ Add to your `bunfig.toml`:
 
 ```toml
 [install.security]
-provider = "@socketsecurity/bun-security-scanner"
+scanner = "@socketsecurity/bun-security-scanner"
 ```
 
 ### Authentication (Optional)