Merge pull request #140 from jacobweinstock/update-dco-link

Update the DCO link:

## Description

<!--- Please describe what this PR is going to change -->
Previous link reference didn't exist.

## Why is this needed

<!--- Link to issue you have raised -->

Fixes: #132 

## How Has This Been Tested?
<!--- Please describe in detail how you tested your changes. -->
<!--- Include details of your testing environment, and the tests you ran to -->
<!--- see how your change affects other areas of the code, etc. -->


## How are existing users impacted? What migration steps/scripts do we need?

<!--- Fixes a bug, unblocks installation, removes a component of the stack etc -->
<!--- Requires a DB migration script, etc. -->


## Checklist:

I have:

- [ ] updated the documentation and/or roadmap (if required)
- [ ] added unit or e2e tests
- [ ] provided instructions on how to upgrade

CONTRIBUTING.md

@@ -13,7 +13,7 @@ Please read and understand the code of conduct found [here](https://github.com/t
 
 ### DCO Sign Off
 
-Please read and understand the DCO found [here](docs/DCO.md).
+Please read and understand the DCO found [here](https://github.com/tinkerbell/org/blob/main/DCO.md).
 
 ### Environment Details