Use semver-granular cooldowns for bundler dependabot ecosystem

Replaces the generic default-days cooldown with semver-granular values so
low-risk patches flow faster while major bumps get more soak time. Also
corrects github-actions cooldown from 10 days to 7 days.

Author: flavorjones

.github/dependabot.yml

@@ -9,7 +9,10 @@ updates:
     development-dependencies:
       dependency-type: "development"
   cooldown:
-    default-days: 10
+    semver-major-days: 7
+    semver-minor-days: 3
+    semver-patch-days: 2
+    default-days: 7
 - package-ecosystem: github-actions
   directory: "/"
   groups:
@@ -20,4 +23,4 @@ updates:
     interval: weekly
   open-pull-requests-limit: 10
   cooldown:
-    default-days: 10
+    default-days: 7