update button asset to use github repo

Author: nullfunc

README.md

@@ -1,6 +1,6 @@
 # Sveltekit & MongoDB
 
-[![1-click-deploy](https://defang.io/deploy-with-defang.svg)](https://portal.defang.dev/redirect?url=https%3A%2F%2Fgithub.com%2Fnew%3Ftemplate_name%3Dsample-sveltekit-mongodb-template%26template_owner%3DDefangSamples)
+[![1-click-deploy](https://raw.githubusercontent.com/DefangLabs/defang-assets/main/Logos/Buttons/SVG/deploy-with-defang.svg)](https://portal.defang.dev/redirect?url=https%3A%2F%2Fgithub.com%2Fnew%3Ftemplate_name%3Dsample-sveltekit-mongodb-template%26template_owner%3DDefangSamples)
 
 This is a project that demonstrate both client side component rendering and hydration as well as serverside rendering with external API route configuration. Furthermore, there is also a mongodb connection (not hosted on the atlas) to cache the queried results.