fix: images/nginx/Dockerfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-ALPINE315-LIBWEBP-5902238
- https://snyk.io/vuln/SNYK-ALPINE315-NGHTTP2-5964211
- https://snyk.io/vuln/SNYK-ALPINE315-CURL-2938004
- https://snyk.io/vuln/SNYK-ALPINE315-CURL-3320718
- https://snyk.io/vuln/SNYK-ALPINE315-CURL-5958915

Author: snyk-bot

images/nginx/Dockerfile

@@ -1,4 +1,4 @@
-FROM nginx:1.21.6-alpine
+FROM nginx:1.26.3-alpine
 
 COPY ./conf/nginx.conf /etc/nginx/nginx.conf
 COPY ./conf/network_internal.conf /etc/nginx/