[MNT] update dependabot.yml for daily updates (#609)

Makes minor updates to `dependabot` behaviour:

* daily updates
* use `maintenance` label and `[MNT]` prefix in description

Author: fkiraly

.github/dependabot.yml

@@ -1,38 +1,21 @@
-# Basic dependabot.yml file with minimum configuration for two package managers
-
 version: 2
 updates:
-    # Enable version updates for python
-    - package-ecosystem: "pip"
-      # Look for a `requirements` in the `root` directory
-      directory: "/"
-      # Check for updates once a week
-      schedule:
-          interval: "monthly"
-      # Labels on pull requests for version updates only
-      labels:
-          - "dependencies"
-      pull-request-branch-name:
-          # Separate sections of the branch name with a hyphen for example, `dependabot-npm_and_yarn-next_js-acorn-6.4.1`
-          separator: "-"
-      # Allow up to 5 open pull requests for pip dependencies
-      open-pull-requests-limit: 5
-      reviewers:
-          - "manujosephv"
+  - package-ecosystem: "pip"
+    directory: "/"
+    schedule:
+      interval: "daily"
+    commit-message:
+      prefix: "[MNT] [Dependabot]"
+      include: "scope"
+    labels:
+      - "maintenance"
 
-    # Enable version updates for GitHub Actions
-    - package-ecosystem: "github-actions"
-      directory: "/"
-      # Check for updates once a week
-      schedule:
-          interval: "monthly"
-      # Labels on pull requests for version updates only
-      labels:
-          - "enhancement"
-      pull-request-branch-name:
-          # Separate sections of the branch name with a hyphen for example, `dependabot-npm_and_yarn-next_js-acorn-6.4.1`
-          separator: "-"
-      # Allow up to 5 open pull requests for GitHub Actions
-      open-pull-requests-limit: 5
-      reviewers:
-          - "manujosephv"
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"
+    commit-message:
+      prefix: "[MNT] [Dependabot]"
+      include: "scope"
+    labels:
+      - "maintenance"