chore: update typo in README (#2062)

Author: raresraf

README.md

@@ -68,7 +68,7 @@ to your Cloud SQL instance, you will need to add this library as a jar with depe
 
 Here are some troubleshooting tips to resolve common issues that come up when using the Java Connector:
 
-1. Make sure you are using the latest version of the Cloud SQL Connector and your database driver to avoid incompatibilities. Some older versions of drivers are not supported
+1. Make sure you are using the latest version of the Cloud SQL Connector and your database driver to avoid incompatibilities. Some older versions of drivers are not supported.
 1. The Java connector provides authorization for connections, but it does not provide new paths to connectivity. For example, in order to connect to a Cloud SQL instance using a Private IP address, your application must already have VPC access. 
 
 ## Support policy