docs: Fix bullet point formatting in CONTRIBUTING.md (#893)

Standardizes bullet point formatting for improved readability by removing commas and following consistent style conventions.

Signed-off-by: Alex-Weisberg <[email protected]>

Author: Alex-Weisberg

CONTRIBUTING.md

@@ -4,10 +4,10 @@ Welcome to the Kubeflow project! We'd love to accept your patches and
 contributions to this project. Please read the 
 [contributor's guide in our docs](https://www.kubeflow.org/docs/about/contributing/).
 
-The contributor's guide
+The contributor's guide:
 
-* shows you where to find the Developer Certificate of Origin (DCO) that you need 
-  to agree to,
-* helps you get started with your first contribution to Kubeflow,
-* and describes the pull request and review workflow in detail, including the
-  OWNERS files and automated workflow tool.
+* Shows you where to find the Developer Certificate of Origin (DCO) that you need 
+  to agree to
+* Helps you get started with your first contribution to Kubeflow
+* Describes the pull request and review workflow in detail, including the
+  OWNERS files and automated workflow tool