chore(deps): update lscr.io/linuxserver/heimdall docker tag to v2.7.6 (#1456)

* chore(deps): update lscr.io/linuxserver/heimdall docker tag to v2.7.6

* chore: sync template versions with image updates

---------

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

library/compose/heimdall/compose.yaml.j2

@@ -1,6 +1,6 @@
 services:
   heimdall:
-    image: lscr.io/linuxserver/heimdall:2.7.4
+    image: lscr.io/linuxserver/heimdall:2.7.6
     container_name: heimdall
     environment:
       - PUID=1000

library/compose/heimdall/template.yaml

@@ -10,9 +10,9 @@ metadata:
     Project: https://heimdall.site/
 
     Documentation: https://docs.heimdall.site/
-  version: 2.7.4
+  version: 2.7.6
   author: Christian Lempa
-  date: '2025-09-28'
+  date: '2025-10-31'
   tags:
     - dashboard
   draft: true