CONTRIBUTING: Document PR approval and link to OWNERS

Remove a dead "Becoming a Maintainer" link and that stub section,
since libpod currently doesn't document that process.  By leaving it
undocumented, maintainer changes falls back to the usual pull-request
review process.

Signed-off-by: W. Trevor King <wking@tremily.us>

Closes: #688
Approved by: rhatdan

CONTRIBUTING.md

@@ -8,7 +8,6 @@ that we follow.
 * [Reporting Issues](#reporting-issues)
 * [Submitting Pull Requests](#submitting-pull-requests)
 * [Communications](#communications)
-* [Becoming a Maintainer](#becoming-a-maintainer)
 
 ## Reporting Issues
 
@@ -55,9 +54,7 @@ PRs that fix issues should include a reference like `Closes #XXXX` in the
 commit message so that github will automatically close the referenced issue
 when the PR is merged.
 
-<!--
-All PRs require at least two LGTMs (Looks Good To Me) from maintainers.
--->
+PRs will be approved by an [approver][owners] listed in [`OWNERS`](OWNERS).
 
 ### Sign your PRs
 
@@ -124,18 +121,4 @@ and
 [PRs](https://github.com/projectatomic/libpod/pulls)
 tracking system.
 
-<!--
-## Becoming a Maintainer
-
-To become a maintainer you must first be nominated by an existing maintainer.
-If a majority (>50%) of maintainers agree then the proposal is adopted and
-you will be added to the list.
-
-Removing a maintainer requires at least 75% of the remaining maintainers
-approval, or if the person requests to be removed then it is automatic.
-Normally, a maintainer will only be removed if they are considered to be
-inactive for a long period of time or are viewed as disruptive to the community.
-
-The current list of maintainers can be found in the
-[MAINTAINERS](MAINTAINERS) file.
--->
+[owners]: https://github.com/kubernetes/community/blob/master/contributors/guide/owners.md#owners