Add a 7-day cooldown to Dependabot updates

Fixes #190.

Assisted-by: Claude Opus 5.5

Author: skritosss

.github/dependabot.yml

@@ -12,18 +12,26 @@ updates:
     directory: "/"
     patterns: ["*"]
     multi-ecosystem-group: "dependencies"
+    cooldown:
+      default-days: 7
 
   - package-ecosystem: "pip"
     directory: "/"
     patterns: ["*"]
     multi-ecosystem-group: "dependencies"
+    cooldown:
+      default-days: 7
 
   - package-ecosystem: "pip"
     directory: "/pth-tester"
     patterns: ["*"]
     multi-ecosystem-group: "dependencies"
+    cooldown:
+      default-days: 7
 
   - package-ecosystem: "pre-commit"
     directory: "/"
     patterns: ["*"]
     multi-ecosystem-group: "dependencies"
+    cooldown:
+      default-days: 7