Bump eec-campaigns pin to v0.1.6

Sent/running campaigns are now skipped (not rejected) during sync, so a
finished campaign like 2026-07-23-iron-rose-proof-approved no longer has
to be deleted just to keep sync green.

.gitea/workflows/sync-template.yml

@@ -13,7 +13,7 @@ jobs:
           go-version: "1.23.1"
 
       - name: Install eec-campaigns
-        run: go install gitea.reground.org/will/eec-campaigns@v0.1.5
+        run: go install gitea.reground.org/will/eec-campaigns@v0.1.6
 
       - name: Sync template to listmonk
         run: eec-campaigns template "sunfloweracres default" email-templates/campaign.html