Enable dependabot (#3340)

diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644
index 0000000..ab8774e
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,7 @@
+version: 2
+enable-beta-ecosystems: true
+updates:
+  - package-ecosystem: "pub"
+    directory: "/"
+    schedule:
+      interval: "monthly"