Merge PR Template to Contributing

    - Remove pull request template.
    - Add check list in contributing as a kind of TL;DR for that file.

CONTRIBUTING.md

 # Contributing guidelines
 
+## Pull Request Checklist
+
+Before sending your pull requests, make sure you followed this list.
+
+- [ ] Read [contributing guidelines](CONTRIBUTING.md).
+- [ ] Read [Code of Conduct](CODE_OF_CONDUCT.md).
+- [ ] Ensure you have signed the [Contributor License Agreement (CLA)](https://cla.developers.google.com/).
+- [ ] Check if my changes are consistent with the [guidelines](https://github.com/tensorflow/tensorflow/blob/master/CONTRIBUTING.md#general-guidelines-and-philosophy-for-contribution).
+- [ ] Changes are consistent with the [Coding Style](https://github.com/tensorflow/tensorflow/blob/master/CONTRIBUTING.md#c-coding-style).
+- [ ] Run [Unit Tests](https://github.com/tensorflow/tensorflow/blob/master/CONTRIBUTING.md#running-unit-tests).
+
 ## How to become a contributor and submit your own code
 
 ### Contributor License Agreements

PULL_REQUEST_TEMPLATE.md

-<!-- tensorflow pull request template -->
-
-##### Pull Request Checklist
-<!-- Before sending your pull requests, make sure you followed this list and tick all items -->
-- [ ] Read [contributing guideline](CONTRIBUTING.md).
-- [ ] Read [code of conduct](CODE_OF_CONDUCT.md).
-- [ ] Fill [Contributor License Agreement (CLA)](https://cla.developers.google.com/).
-- [ ] Check if my changes are consistent with the [guidelines](https://github.com/tensorflow/tensorflow/blob/master/CONTRIBUTING.md#general-guidelines-and-philosophy-for-contribution).
-- [ ] Changes are consistent with the [Coding Style](https://github.com/tensorflow/tensorflow/blob/master/CONTRIBUTING.md#c-coding-style)
-- [ ] Run [Unit Tests](https://github.com/tensorflow/tensorflow/blob/master/CONTRIBUTING.md#running-unit-tests).
-
-##### Issue Fix
-<!-- Does this pull request fix any issue ? -->
-- [ ] Yes
-- [ ] No
-
-Fixed issue:
-
-##### Description
-<!-- Detailed description of what you've done -->