chore(deps): pin nginx docker tag to 31bad00

Dockerfile

@@ -1,5 +1,5 @@
 # Use the Nginx image from Docker Hub
-FROM nginx:alpine
+FROM nginx:alpine@sha256:31bad00311cb5eeb8a6648beadcf67277a175da89989f14727420a80e2e76742
 
 # Copy the HTML file to the Nginx document root
 COPY index.html /usr/share/nginx/html