Add health check

Dockerfile

@@ -4,5 +4,13 @@ WORKDIR /project
 RUN ["zola", "build"]
 
 FROM ghcr.io/static-web-server/static-web-server:2.38.1-alpine
+ENV SERVER_HEALTH=true
 WORKDIR /
+RUN apk --no-cache add curl
 COPY --from=zola /project/public /public
+HEALTHCHECK \
+  --interval=30s \
+  --timeout=5s \
+  --start-period=5s \
+  --retries=3 \
+  CMD ["curl", "http://localhost/health"]