Merge pull request #840 from ahrkrak/patch-1

Fix broken link to project proposal process

process/due-diligence-guidelines.md

@@ -34,7 +34,7 @@ validity are ideally resolved, helps to foster this consensus.
 ### Where to start
 
 * Make sure you are clear on the [TOC Principles](https://github.com/cncf/toc/blob/main/PRINCIPLES.md),
- the [project proposal process](https://github.com/cncf/toc/blob/main/process/project_proposals.adoc),
+ the [project proposal process](https://github.com/cncf/toc/blob/main/process/project_proposals.md),
  the [graduation criteria](https://github.com/cncf/toc/blob/main/process/graduation_criteria.adoc),
  and the [desired cloud native properties](https://www.cncf.io/about/charter/). The project sponsor (a member
  of the TOC) should have assisted in crafting the proposal to explain why it is a good fit for the CNCF. If anything is