[Snyk] Security upgrade nginx from mainline-alpine to 1.23.1-alpine (cvat-ai#94)

fix: Dockerfile.ui to reduce vulnerabilities

Author: snyk-bot

Dockerfile.ui

@@ -36,7 +36,7 @@ COPY cvat-canvas/ /tmp/cvat-canvas/
 COPY cvat-ui/ /tmp/cvat-ui/
 RUN yarn run build:cvat-ui
 
-FROM nginx:mainline-alpine
+FROM nginx:1.23.1-alpine
 # Replace default.conf configuration to remove unnecessary rules
 COPY cvat-ui/react_nginx.conf /etc/nginx/conf.d/default.conf
 COPY --from=cvat-ui /tmp/cvat-ui/dist /usr/share/nginx/html/