Merge pull request #649 from netlify/chore/add_pr_template

chore: add PR template

.github/pull_request_template.md

@@ -0,0 +1,17 @@
+🎉 Thanks for submitting a pull request! 🎉
+
+For us to review and ship your PR efficiently, please perform the following steps:
+
+- [ ] Open a [bug/issue](https://github.com/netlify/build-image/issues/new/choose) before writing your code 🧑‍💻. This ensures
+      we can discuss the changes and get feedback from everyone that should be involved. If you\`re fixing a typo or
+      something that\`s on fire 🔥 (e.g. incident related), you can skip this step.
+- [ ] Read the [contribution guidelines](../CONTRIBUTING.md) 📖. This ensures your code follows our style guide and
+      passes our tests.
+- [ ] Update or add tests (if any source code was changed or added) 🧪
+- [ ] Update the [included software doc](../included_software.md) (if you updated included software) 📄
+- [ ] Update or add documentation (if features were changed or added) 📝
+- [ ] Make sure the status checks below are successful ✅
+
+Fixes #<replace_with_issue_number>
+
+**A picture of a cute animal (not mandatory, but encouraged)**