Don't run on dependabot pushes (dupe runs, can't access secrets)

Author: pimterry

.github/workflows/ci.yml

@@ -1,7 +1,9 @@
 name: CI
 on:
-  - push
-  - pull_request
+  push:
+      branches-ignore:
+          - 'dependabot/**'
+  pull_request:
 jobs:
   build:
     name: Build & test