Update petclinic_db_setup_mysql.txt

Hey Team, thanks in advance!

src/main/resources/db/mysql/petclinic_db_setup_mysql.txt

@@ -21,7 +21,7 @@
 2) (Once only) create the PetClinic database and user by executing the "db/mysql/user.sql"
    scripts. You can connect to the database running in the docker container using 
    `mysql -u root -h localhost --protocol tcp`, but you don't need to run the script there
-   because the petclinic user is already set up if you use the provided `docker-compose.yaml`.
+   because the petclinic user is already set up if you use the provided `docker-compose.yml`.
 
 3) Run the app with `spring.profiles.active=mysql` (e.g. as a System property via the command
    line, but any way that sets that property in a Spring Boot app should work). For example use