Add github metadata

.github/CODEOWNERS

@@ -0,0 +1,5 @@
+* @jelmer
+
+# Release robot
+dulwich/contrib/release_robot.py @mikofski
+dulwich/contrib/test_release_robot.py @mikofski

.github/dependabot.yml

@@ -0,0 +1,18 @@
+# Keep GitHub Actions up to date with GitHub's Dependabot...
+# https://docs.github.com/en/code-security/dependabot/working-with-dependabot/keeping-your-actions-up-to-date-with-dependabot
+# https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file#package-ecosystem
+version: 2
+updates:
+  - package-ecosystem: "cargo"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    rebase-strategy: "disabled"
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: weekly
+  - package-ecosystem: "pip"
+    directory: "/"
+    schedule:
+      interval: weekly