ci: set Dependabot commit prefixs

.github/dependabot.yml

@@ -5,6 +5,8 @@ updates:
     directory: "/"
     schedule:
       interval: "daily"
+    commit-message:
+      prefix: "build"
     labels:
       - "type/build"
       - "scope/dockerfile"
@@ -14,5 +16,7 @@ updates:
     directory: "/test/requirements"
     schedule:
       interval: "daily"
+    commit-message:
+      prefix: "ci"
     labels:
       - "type/ci"