ci: run builds periodically

Without big development activity, thus workflows triggered on changes,
CI builds might never run.  In the same time distros actually change, so
things can get be broken due to external (distro) reasons.  This is
especially true for development versions, like Debian testing.

Run at least once per week, to be sure everything still builds even
without development activity.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

.github/workflows/ci.yml

@@ -9,7 +9,13 @@
 #                   https://github.com/linux-nfc/neard
 #
 name: "Builds"
-on: [push, pull_request, workflow_dispatch]
+on:
+  pull_request:
+  push:
+  schedule:
+    # Run at 1:01 PM, every Tuesday
+    - cron: '1 13 * * 2'
+  workflow_dispatch:
 
 jobs:
   job: