Modifies jib-gradle task according to the new reorg proposal

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

This patch also moves the jib-gradle files to the task directory
and modifies the path for install task command in readme file

Issue: #386

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

task/jib-gradle/0.1/README.md

@@ -7,7 +7,7 @@ Jib works with [Gradle](https://github.com/GoogleContainerTools/jib/tree/master/
 ## Install the Task
 
 ```
-kubectl apply -f https://raw.githubusercontent.com/tektoncd/catalog/master/jib-gradle/jib-gradle.yaml
+kubectl apply -f https://raw.githubusercontent.com/tektoncd/catalog/master/task/jib-gradle/0.1/jib-gradle.yaml
 ```
 
 

task/jib-gradle/0.1/jib-gradle.yaml

@@ -2,7 +2,18 @@ apiVersion: tekton.dev/v1beta1
 kind: Task
 metadata:
   name: jib-gradle
+  labels:
+    app.kubernetes.io/version: "0.1"
+  annotations:
+    tekton.dev/pipelines.minVersion: "0.12.1"
+    tekton.dev/tags: image-build
+    tekton.dev/displayName: "jib gradle"
 spec:
+  description: >-
+    This Task builds Java/Kotlin/Groovy/Scala source into a container image using Google’s Jib tool.
+
+    Jib works with Gradle and Maven projects, and this template is for Gradle projects.
+
   params:
   - name: DIRECTORY
     description: The directory containing the app, relative to the source repository root