Fix application.yaml file name typo in config source docs
dont update README.adoc as it is autogenerated
== Kubernetes PropertySource implementations
-The most common approach to configuring your Spring Boot application is to create an `application.properties` or `applicaiton.yaml` or
+The most common approach to configuring your Spring Boot application is to create an `application.properties` or `application.yaml` or
an `application-profile.properties` or `application-profile.yaml` file that contains key-value pairs that provide customization values to your
application or Spring Boot starters. You can override these properties by specifying system properties or environment
variables.
