warn against putting .par file changes in PR. (#342)

.github/PULL_REQUEST_TEMPLATE.md

diff --git a/.github/PULL_REQUEST_TEMPLATE.md b/.github/PULL_REQUEST_TEMPLATE.md
index 38e0658..4e54f41 100644
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -2,6 +2,7 @@
 
 Please check if your PR fulfills the following requirements:
 
+- [ ] Does not include precompiled binaries, eg. `.par` files. See [CONTRIBUTING.md](/CONTRIBUTING.md) for info
 - [ ] Tests for the changes have been added (for bug fixes / features)
 - [ ] Docs have been added / updated (for bug fixes / features)