Format README

README.md

@@ -172,7 +172,7 @@ utils.convertFromISODateString(isoDateString: string): Date;
 utils.convertMilliUnitsToCurrencyAmount(milliunits: number, currencyDecimalDigits: number): number;
 ```
 
-### Versioning
+## Versioning
 
 The version of this client is defined in the `package.json` file and follows [semantic versioning](https://semver.org/).  The version of this client is maintained independently and does not align with the the version of YNAB API itself (which is defined in the [OpenAPI spec](https://api.ynab.com/papi/open_api_spec.yaml)).  To determine which spec version of the YNAB API was used when generating this client you can refer to the `description` field in the `package.json` file.