Add details about the binding file permissions

Author: beyhan

toc/rfc/rfc-draft-add-support-for-file-based-service-binding.md

@@ -86,7 +86,7 @@ Additionally, the suggest limit for the size should be implemented.
 
 ### App Runtime Platform WG
 
-Diego should add support for the new argument of the Run action to create files with the desired content. Like the [Instance Identity credentials](https://docs.cloudfoundry.org/devguide/deploy-apps/instance-identity.html) implementation, the [Diego Executor](https://github.com/cloudfoundry/executor) should be extended to prepare the `tmpfs` mount and create the required files for an application container. For reference there is a [CredManager](https://github.com/cloudfoundry/executor/blob/db9758c0142ae9c11dad26de672735fb20566105/depot/containerstore/credmanager.go) , InstanceIdentityHandler and the `tmpfs` mount is configured in the [Diego release](https://github.com/cloudfoundry/diego-release/blob/2d7d7c1373f2a61077c74e33a397a5f69b11b131/jobs/rep/templates/setup_mounted_data_dirs.erb#L38-L56) for the current implementation of the Instance Identity Credentials.
+Diego should add support for the new argument of the Run action to create files with the desired content. Like the [Instance Identity credentials](https://docs.cloudfoundry.org/devguide/deploy-apps/instance-identity.html) implementation, the [Diego Executor](https://github.com/cloudfoundry/executor) should be extended to prepare the `tmpfs` mount and create the required files for an application container. For reference there is a [CredManager](https://github.com/cloudfoundry/executor/blob/db9758c0142ae9c11dad26de672735fb20566105/depot/containerstore/credmanager.go) , InstanceIdentityHandler and the `tmpfs` mount is configured in the [Diego release](https://github.com/cloudfoundry/diego-release/blob/2d7d7c1373f2a61077c74e33a397a5f69b11b131/jobs/rep/templates/setup_mounted_data_dirs.erb#L38-L56) for the current implementation of the Instance Identity Credentials. The files should have security permissions like the Instance Identity Credentilas `644` or even higher `600` owned by the uid running the app if possible.
 
 ## Possible Future Work