Adds PR template (fixes ryanoasis#66)

* adds first version of pull request template to help users with contributing

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,25 @@
+
+#### Description
+
+_Please explain the changes you made here._
+
+#### Requirements / Checklist
+
+- [ ] Read the [Contributing Guidelines](https://github.com/ryanoasis/nerd-fonts/blob/master/contributing.md)
+- [ ] Read or at least glanced at the [FAQ](https://github.com/ryanoasis/nerd-fonts#faq)
+- [ ] Read or at least glanced at the [Wiki](https://github.com/ryanoasis/nerd-fonts/wiki)
+- [ ] Scripts execute without error (if necessary):
+  - If any of the scripts were modified they have been tested and execute without error, e.g.:
+    - `./font-patcher Inconsolata.otf --fontawesome --octicons --pomicons`
+    - `./gotta-patch-em-all-font-patcher\!.sh Hermit`
+- [ ] Extended the README and documentation if necessary, e.g. You added a new font please update the table
+
+#### What does this Pull Request (PR) do?
+
+#### How should this be manually tested?
+
+#### Any background context you can provide?
+
+#### What are the relevant tickets (if any)?
+
+#### Screenshots (if appropriate or helpful)