add note about default branch name in postgresql conenction string

020-Connect/010-Postgres/001-direct-access.mdx

@@ -40,6 +40,7 @@ With the mapping from above, the connection string to connect to our database `G
 postgresql://ws1234:[email protected]:5432/Games:main?sslmode=require
 ```
 
+- The default branch is `main`. If you do not specify a branch name in the connection string, you connect to your `main` branch.
 - The connection strings for HTTP access and Postgres wire protocol access are shown to you when you create a new database. You can view this connection string at any time by going to your database's settings page.
 - API keys are stored at the user level and can be accessed within [account settings](https://app.xata.io/settings).