remove return line from first line (#772)

Author: AlexandreKempf

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,5 +1,4 @@
-- [ ] ❗ I have followed the [Contributing to DVCLive](https://github.com/iterative/dvclive/blob/main/CONTRIBUTING.rst)
-  guide.
+- [ ] ❗ I have followed the [Contributing to DVCLive](https://github.com/iterative/dvclive/blob/main/CONTRIBUTING.rst) guide.
 
 - [ ] 📖 If this PR requires [documentation](https://dvc.org/doc) updates, I have created a separate PR (or issue, at least) in [dvc.org](https://github.com/iterative/dvc.org) and linked it here.