fix: Corrects typo in pull_request_template.md

[darigovresearch]

Description

Changes any additionl context to any additional context. Would resolve issue #17

Affected Dependencies

None

How has this been tested?

In GitHub via the browser

Checklist

• [x] I have followed the Contribution Guidelines and Code of Conduct
• [x] I have commented my code following the OpenMined Styleguide
• [x] I have labeled this PR with the relevant Type labels
• [x] My changes are covered by tests

[darigovresearch]

Can someone please take a look at this to be merged?

Having this as an open fork is causing OpenMined links to be on all of our open source repositories even when it is not pertinent to the project

Thanks