Add detect-secret pre-commit hook.

.pre-commit-config.yaml

@@ -83,3 +83,7 @@ repos:
     hooks:
       - id: bandit
         exclude: *excluded_pythonscripts
+  - repo: https://github.com/Yelp/detect-secrets
+    rev: v0.13.0
+    hooks:
+      - id: detect-secrets