Add manual validation checks to comply with Catalog Org TEP

We would need to ensure that the PR submissions are manually validated
against the [TEP-003] until we have the [validation tool] added to CI.

Signed-off-by: Sunil Thaha <[email protected]>

---

[TEP-003]: https://github.com/tektoncd/community/blob/master/teps/0003-tekton-catalog-organization.md
[validation tool]: tektoncd#413

.github/pull_request_template.md

@@ -13,6 +13,25 @@ review them:
 - [ ] Includes [docs](https://github.com/tektoncd/community/blob/master/standards.md#principles) (if user facing)
 - [ ] Commit messages follow [commit message best practices](https://github.com/tektoncd/community/blob/master/standards.md#commit-messages)
 - [ ] Yaml file complies with [yamllint](https://github.com/adrienverge/yamllint) rules.
+- [ ] Complies with [Catalog Orgainization TEP][TEP], see [example]. **Note** [An issue has been filed to automate this validation][validation]
+  - [ ] File path follows  `<kind>/<name>/<version>/name.yaml`
+  - [ ] Has `README.md` at `<kind>/<name>/<version>/README.md`
+  - [ ] Has mandatory `metadata.labels` - `app.kubernetes.io/version` the same as the `<version>` of the resource
+  - [ ] Has mandatory `metadata.annotations` `tekton.dev/pipelines.minVersion`
+  - [ ] mandatory `spec.description` follows the convention
+        ```yaml
+        spec:
+          description: >-
+            one line summary of the resource
+
+            Paragraph(s) to describe the resource.
+        ```
 
 _See [the contribution guide](https://github.com/tektoncd/catalog/blob/master/CONTRIBUTING.md)
 for more details._
+
+---
+
+[TEP]: https://github.com/tektoncd/community/blob/master/teps/0003-tekton-catalog-organization.md
+[example]: https://github.com/tektoncd/catalog/tree/master/task/git-clone/0.1
+[validation]:  https://github.com/tektoncd/catalog/issues/413