[stable/prometheus-adapter] Add myself to OWNERS (#13887)

Signed-off-by: Steven Sheehy <ssheehy@firescope.com>

stable/prometheus-adapter/Chart.yaml

@@ -1,11 +1,12 @@
 apiVersion: v1
 name: prometheus-adapter
-version: 1.0.1
+version: 1.0.2
 appVersion: v0.5.0
 description: A Helm chart for k8s prometheus adapter
 home: https://github.com/DirectXMan12/k8s-prometheus-adapter
 keywords:
   - hpa
+  - metrics
   - prometheus
   - adapter
 sources:
@@ -14,3 +15,4 @@ sources:
 maintainers:
   - name: mattiasgees
     email: mattias.gees@jetstack.io
+  - name: steven-sheehy

stable/prometheus-adapter/OWNERS

@@ -0,0 +1,6 @@
+approvers:
+  - mattiasgees
+  - steven-sheehy
+reviewers:
+  - mattiasgees
+  - steven-sheehy