Update Dockerfile

Dockerfile

@@ -1,5 +1,10 @@
-# Use an Alpine-based image that includes a shell
-FROM portainer/portainer-ce:latest-alpine
+# Use Alpine as the base image
+FROM alpine:latest
+
+# Install Portainer
+RUN apk add --no-cache curl && \
+    curl -L https://github.com/portainer/portainer-ce/releases/latest/download/portainer-ce-linux-amd64 -o /usr/local/bin/portainer && \
+    chmod +x /usr/local/bin/portainer
 
 # Copy the entry point script
 COPY start.sh /start.sh