add PR request template (#154)

Author: renatocmaciel

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,5 @@
+- [ ] closes #xxxx (Replace xxxx with the GitHub issue number)
+- [ ] `Tests added and passed` if fixing a bug or adding a new feature.
+- [ ] All `code checks passed`.
+- [ ] Added `type annotations` to new arguments/methods/functions.
+- [ ] Updated documentation.