Added plugin to marketplace

Signed-off-by: Brett Wright <wright.brett@gmail.com>

microsite/data/plugins/gke-usage.yaml

@@ -0,0 +1,15 @@
+---
+title: GKE Usage
+author: BESTSELLER
+authorUrl: bestsellerit.com
+category: Discovery # A single category e.g. CI, Machine Learning, Services, Monitoring
+description: This plugin will show you the cost and resource usage of your application within GKE. # Max 170 characters
+documentation: https://github.com/BESTSELLER/backstage-plugin-gkeusage/blob/master/README.md
+iconUrl: https://bestsellerit.com/img/google-container-engine_avatar.svg
+npmPackageName: '@bestsellerit/backstage-plugin-gkeusage'
+tags:
+  - gke
+  - cost
+  - google
+  - usage
+  - metering