Create dependabot.yml

Bumps [commonmarker](https://github.com/gjtorikian/commonmarker) from 0.23.6 to 0.23.7.
- [Release notes](https://github.com/gjtorikian/commonmarker/releases)
- [Changelog](https://github.com/gjtorikian/commonmarker/blob/main/CHANGELOG.md)
- [Commits](https://github.com/gjtorikian/commonmarker/compare/v0.23.6...v0.23.7)

---
updated-dependencies:
- dependency-name: commonmarker
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/dependabot.yml

@@ -0,0 +1,11 @@
+# To get started with Dependabot version updates, you'll need to specify which
+# package ecosystems to update and where the package manifests are located.
+# Please see the documentation for all configuration options:
+# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+
+version: 2
+updates:
+  - package-ecosystem: "bundler" # See documentation for possible values
+    directory: "/" # Location of package manifests
+    schedule:
+      interval: "weekly"

Gemfile.lock

@@ -1,7 +1,7 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    activesupport (6.0.5)
+    activesupport (~> 6.0.5)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)
@@ -14,7 +14,7 @@ GEM
       execjs
     coffee-script-source (1.11.1)
     colorator (1.1.0)
-    commonmarker (0.23.6)
+    commonmarker (0.23.7)
     concurrent-ruby (1.1.10)
     dnsruby (1.61.9)
       simpleidn (~> 0.1)