sig-release: Add testgrid-json-exporter repo

Related:
  - kubernetes/org#3218

Signed-off-by: Arnaud Meukam <[email protected]>

Author: ameukam

sig-release/README.md

@@ -72,6 +72,7 @@ The Release Engineering subproject is responsible for the [process/procedures](h
   - [kubernetes-sigs/release-notes](https://github.com/kubernetes-sigs/release-notes/blob/master/OWNERS)
   - [kubernetes-sigs/release-sdk](https://github.com/kubernetes-sigs/release-sdk/blob/main/OWNERS)
   - [kubernetes-sigs/release-utils](https://github.com/kubernetes-sigs/release-utils/blob/main/OWNERS)
+  - [kubernetes-sigs/testgrid-json-exporter](https://github.com/kubernetes-sigs/testgrid-json-exporter/blob/main/OWNERS)
   - [kubernetes-sigs/zeitgeist](https://github.com/kubernetes-sigs/zeitgeist/blob/master/OWNERS)
   - [kubernetes/kubernetes/CHANGELOG](https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG/OWNERS)
   - [kubernetes/kubernetes/build/build-image](https://github.com/kubernetes/kubernetes/blob/master/build/build-image/OWNERS)

sigs.yaml

@@ -2151,6 +2151,7 @@ sigs:
     - https://raw.githubusercontent.com/kubernetes-sigs/release-notes/master/OWNERS
     - https://raw.githubusercontent.com/kubernetes-sigs/release-sdk/main/OWNERS
     - https://raw.githubusercontent.com/kubernetes-sigs/release-utils/main/OWNERS
+    - https://raw.githubusercontent.com/kubernetes-sigs/testgrid-json-exporter/main/OWNERS
     - https://raw.githubusercontent.com/kubernetes-sigs/zeitgeist/master/OWNERS
     - https://raw.githubusercontent.com/kubernetes/kubernetes/master/CHANGELOG/OWNERS
     - https://raw.githubusercontent.com/kubernetes/kubernetes/master/build/build-image/OWNERS