Add missing newline in prec-commit-config.yaml

Just to be sure the coming linting won't be disturbed by that.

Author: Byron

Diff for: .pre-commit-config.yaml

@@ -25,4 +25,4 @@ repos:
 - repo: https://github.com/abravalheri/validate-pyproject
   rev: v0.16
   hooks:
-    - id: validate-pyproject
+    - id: validate-pyproject