chore(ci): add gitleaks in pre-commit hooks as an extra safety measure (aws-powertools#2677)

Co-authored-by: Heitor Lessa <[email protected]>

Author: step-security-bot

Diff for: .github/dependabot.yml

@@ -71,3 +71,8 @@ updates:
     directory: /layer/scripts/layer-balancer
     schedule:
       interval: daily
+
+  - package-ecosystem: pip
+    directory: /docs
+    schedule:
+      interval: daily

Diff for: .pre-commit-config.yaml

@@ -46,3 +46,7 @@ repos:
       - id: terraform_fmt
         args:
           - --args=-recursive
+  - repo: https://github.com/gitleaks/gitleaks
+    rev: "7804d652c0460f0b61ea9bb2c1f202bfcdbbf144" # v8.16.3
+    hooks:
+      - id: gitleaks