Remove defunct owners, add new owners (#873)

* Remove brandjon, lberki, thundergolfer; they're no longer active
   in the repo.
 * Add rickeylev as replacement owner.
diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index 073f698..a35be61 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -1,21 +1,6 @@
 # NB: Last matching rule takes precedence in CODEOWNERS.
 
-# Fall-through to community maintainers.
-* @thundergolfer
-
-# Core Python rules belong to the Bazel team.
-/python/ @brandjon @lberki
-# But not everything under python/ is the core Python rules.
-/python/pip.bzl @thundergolfer
-/python/requirements.txt @thundergolfer
+* @rickeylev
 
 # Directory containing the Gazelle extension and Go code.
 /gazelle/ @f0rmiga
-
-# The proposals dir corresponds to the Bazel proposals process, documented
-# here: https://bazel.build/designs/index.html
-/proposals/ @brandjon @lberki
-
-# Certain repo metadata files should stay as-is, particularly these.
-/LICENSE @brandjon @lberki
-/CONTRIBUTING.md @brandjon @lberki