algo/PULL_REQUEST_TEMPLATE.md

<!--- Provide a general summary of your changes in the Title above -->

## Description
<!--- Describe your changes in detail -->

## Motivation and Context
<!--- Why is this change required? What problem does it solve? -->
<!--- If it fixes an open issue, please link to the issue here. -->

## How Has This Been Tested?
<!--- Please describe in detail how you tested your changes. -->
<!--- Include details of your testing environment, tests ran to see how -->
<!--- your change affects other areas of the code, etc. -->

## Types of changes
<!--- What types of changes does your code introduce? Put an `x` in all the boxes that apply: -->
- Bug fix (non-breaking change which fixes an issue)
- New feature (non-breaking change which adds functionality)
- Breaking change (fix or feature that would cause existing functionality to not work as expected)

## Checklist:
<!--- Go over all the following points, and put an `x` in all the boxes that apply. -->
<!--- If you're unsure about any of these, don't hesitate to ask. We're here to help! -->
- [] I have read the **CONTRIBUTING** document.
- [] My code follows the code style of this project.
- [] My change requires a change to the documentation.
- [] I have updated the documentation accordingly.
- [] I have added tests to cover my changes.
- [] All new and existing tests passed.