docs: update acceptance test doc (#5058)

* docs: update guidance on running acceptance tests locally

* docs: update acceptance tests

CONTRIBUTING.md

@@ -105,6 +105,12 @@ Use [fake-server](./test/acceptance/fake-server.ts) to mock any Snyk API calls.
 
 Place fixtures in `./test/fixtures`. Keep them minimal to reduce maintenance. Use [`createProject`](./test/jest/util/createProject.ts) to use your fixtures in isolated working directories for your tests.
 
+Before running the tests locally you will need to:
+
+- Set the `TEST_SNYK_TOKEN` environment variable with a [valid API token](https://docs.snyk.io/snyk-api/authentication-for-api).
+- Run `make build` to ensure you have binary
+- Set `TEST_SNYK_COMMAND` to the path of the built binary for your environment, for example: `./binary-releases/snyk-macos`
+
 You can run acceptance tests with:
 
 ```