Link to docker's contrib workflow

This will aid people in how to make pull requests for code and docs.

Signed-off-by: Mazz Mosley <[email protected]>

CONTRIBUTING.md

@@ -30,6 +30,10 @@ that should get you started.
    `docker-compose` from anywhere on your machine, it will run your development
    version of Compose.
 
+## Submitting a pull request
+
+See docker's [basic contribution workflow](https://docs.docker.com/project/make-a-contribution/#the-basic-contribution-workflow) for a guide on how to submit a pull request for code or documentation.
+
 ## Running the test suite
 
 Use the test script to run linting checks and then the full test suite against