Fix up deploy previews (#749)

fix(ci): deploy previews

---------

Co-authored-by: Bastien Wirtz <bastien.wirtz@gmail.com>

dummy-data/_headers

@@ -1,5 +1,2 @@
 /*
   Content-Type: application/json
-  Access-Control-Allow-Origin: https://homer-demo.netlify.app
-  Access-Control-Allow-Headers: Authorization
-  Access-Control-Allow-Methods: GET, OPTIONS

public/assets/config-demo.yml.dist

@@ -104,19 +104,19 @@ services:
       - name: "Octoprint"
         logo: "https://cdn-icons-png.flaticon.com/512/3112/3112529.png"
         apikey: "xxxxxxxxxxxx"
-        endpoint: "https://homer-demo-content.netlify.app/octoprint"
+        endpoint: "/dummy-data/octoprint"
         type: "OctoPrint"
       - name: "Pi-hole"
         logo: "https://cdn.jsdelivr.net/gh/walkxcode/dashboard-icons/png/pi-hole.png"
         url: "https://pi-hole.net/"
-        endpoint: "https://homer-demo-content.netlify.app/pihole"
+        endpoint: "/dummy-data/pihole"
         type: "PiHole"
       - name: "Proxmox - Node1"
         logo: "https://cdn.jsdelivr.net/gh/walkxcode/dashboard-icons/png/proxmox.png"
         type: "Proxmox"
         tag: "sys"
         url: "https://www.proxmox.com/en/"
-        endpoint: "https://homer-demo-content.netlify.app/proxmox"
+        endpoint: "/dummy-data/proxmox"
         node: "node1"
         warning_value: 50
         danger_value: 80
@@ -125,7 +125,7 @@ services:
         location: "Lille"
         apikey: "xxxxxxxxxxxx" # insert your own API key here. Request one from https://openweathermap.org/api.
         units: "metric"
-        endpoint: "https://homer-demo-content.netlify.app/openweather/weather"
+        endpoint: "/dummy-data/openweather/weather"
         type: "OpenWeather"
   - name: "Ressources"
     icon: "fa-regular fa-bookmark"