Minor docs updates [skip ci]

Author: benjamin-maynard

README.md

@@ -25,7 +25,7 @@ The below table lists all of the Environment Variables that are configurable for
 | TARGET_DATABASE_NAMES       | **(Required)** Name of the databases to dump. This should be comma seperated (e.g. `database1,database2`).       |
 | TARGET_DATABASE_USER        | **(Required)** Username to authenticate to the database with.                                                    |
 | TARGET_DATABASE_PASSWORD    | **(Required)** Password to authenticate to the database with. Should be configured using a Secret in Kubernetes. |
-| BACKUP_TIMESTAMP            | **(Required)** FORMAT of [date](http://man7.org/linux/man-pages/man1/date.1.html) which added to dump filename. Emty string if no need.                                                                                                                          |
+| BACKUP_TIMESTAMP            | **(Optional)** Date string to append to the backup filename ([date](http://man7.org/linux/man-pages/man1/date.1.html) format). Leave unset if using S3 Versioning and date stamp is not required.                                                                                                                          |
 | SLACK_ENABLED               | **(Optional)** (true/false) Enable or disable the Slack Integration (Default False).                             |
 | SLACK_USERNAME              | **(Optional)** (true/false) Username to use for the Slack Integration (Default: kubernetes-s3-mysql-backup).            |
 | SLACK_CHANNEL               | **(Required if Slack enabled)** Slack Channel the WebHook is configured for.                                     |