Modifies build-push-gke-deploy task from gke-deploy directory according to the new reorg proposal

**NOTE: This only modifies the content of the yaml, changing
        the location of the file will be done in a different
        commit to make review easier

Changes include:
  - adds version label
  - adds a minimum pipeline versions supported by the task
  - adds tags for task
  - adds display name for task
  - modified description to add a summary

Issue: #386

Signed-off-by: Shiv Verma <shverma@redhat.com>

gke-deploy/build-push-gke-deploy.yaml

@@ -2,7 +2,16 @@ apiVersion: tekton.dev/v1beta1
 kind: Task
 metadata:
   name: build-and-push
+  labels:
+    app.kubernetes.io/version: "0.1"
+  annotations:
+    tekton.dev/pipelines.minVersion: "0.12.1"
+    tekton.dev/tags: deploy
 spec:
+  description: >-
+    This Pipeline builds, pushes, and deploys your application to a Google Kubernetes
+    Engine cluster using gke-deploy.
+
   params:
   - name: pathToContext
     description: The path to the build context relative to your source repo's root. This is used by Kaniko.