Add 'check-json' hook.

.pre-commit-config.yaml

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index b528407..9288d5e 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,8 +1,9 @@
 -   repo: git@github.com:pre-commit/pre-commit-hooks
-    sha: ba52312ee8a95ca1b075ee864f3ab78bd5f592a4
+    sha: 243fe50bc119bc5f72be76fc4e3de260ee6f64f1
     hooks:
     -   id: trailing-whitespace
     -   id: end-of-file-fixer
+    -   id: check-json
     -   id: check-yaml
     -   id: debug-statements
     -   id: name-tests-test