Tell trunk to pre-install perltidy

See: trunk-io/plugins#806 (comment)

.trunk/setup-ci/action.yaml

@@ -0,0 +1,9 @@
+name: Trunk Check setup
+description: Set up dependencies for Trunk Check
+
+runs:
+  using: composite
+  steps:
+    - name: Install perltidy
+      shell: bash
+      run: sudo apt update && sudo apt install --yes --no-install-recommends --no-install-suggests perltidy