chore: add ref crowdstrike token in instructions

Author: hazcod

README.md

@@ -7,7 +7,8 @@ Nags users on Slack about outstanding application vulnerabilities found by Crowd
 
 1. Tag your Falcon hosts with `email/user/company/com` if their email is `[email protected]`.
 2. Fetch a binary release or Docker image from [Releases](https://github.com/hazcod/crowdstrike-spotlight-slacker/releases).
-3. Create a configuration file:
+3. Create a Falcon API token to use in `API Clients and Keys` with `Read` permission to `Hosts` and `Spotlight`.
+4. Create a configuration file:
 
 ```yaml
 slack: