Set up Dependabot version updates

.github/dependabot.yml

@@ -0,0 +1,42 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    schedule:
+      interval: "monthly"
+
+  - package-ecosystem: "npm"
+    directory: "/frontend"
+    schedule:
+      interval: "monthly"
+    groups:
+      dev-dependencies:
+        applies-to: "version-updates"
+        dependency-type: "development"
+        exclude-patterns:
+          # These dependencies are responsible for code generation. Updating them
+          # likely also requires regenerating code, so it’s a good idea to update
+          # them separately from other dev dependencies.
+          - "@hey-api/*"
+
+  - package-ecosystem: "docker"
+    directory: "/frontend"
+    schedule:
+      interval: "monthly"
+
+  - package-ecosystem: "pip"
+    directory: "/backend"
+    schedule:
+      interval: "monthly"
+    groups:
+      dev-dependencies:
+        applies-to: "version-updates"
+        dependency-type: "development"
+        exclude-patterns:
+          # Maintain option to merge typeshed packages separately, to ensure they
+          # are in sync with the respective package.
+          - "types-*"
+
+  - package-ecosystem: "docker"
+    directory: "/frontend"
+    schedule:
+      interval: "monthly"