improve dependabot.yml

Author: bayashi

.github/dependabot.yml

@@ -5,9 +5,15 @@ updates:
 - package-ecosystem: "gomod"
   directory: "/"
   schedule:
-    interval: "weekly"
+    interval: "monthly"
+  ignore:
+    - dependency-name: "*"
+      update-types: ["version-update:semver-major", "version-update:semver-patch"]
 
 - package-ecosystem: "github-actions"
   directory: "/"
   schedule:
-    interval: "weekly"
+    interval: "monthly"
+  ignore:
+    - dependency-name: "*"
+      update-types: ["version-update:semver-major", "version-update:semver-patch"]