dependabot: set cooldown.default-days to 4

After further consideration, I'm convinced by the arguments in favor of
using dependency cooldowns to reduce exposure to supply-chain attacks:

https://blog.yossarian.net/2025/11/21/We-should-all-be-using-dependency-cooldowns

Remove suppression of https://docs.zizmor.sh/audits/#dependabot-cooldown

Signed-off-by: Kevin Locke <[email protected]>

Author: kevinoid

.github/dependabot.yml

@@ -2,11 +2,15 @@
 # https://docs.github.com/code-security/supply-chain-security/configuration-options-for-dependency-updates
 version: 2
 updates:
-- package-ecosystem: "github-actions"  # zizmor: ignore[dependabot-cooldown]
+- package-ecosystem: "github-actions"
   directory: "/"
   schedule:
     interval: "daily"
-- package-ecosystem: "pip"  # zizmor: ignore[dependabot-cooldown]
+  cooldown:
+    default-days: 4
+- package-ecosystem: "pip"
   directory: "/"
   schedule:
     interval: "daily"
+  cooldown:
+    default-days: 4