fix: images/main/alpine/Dockerfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-ALPINE318-CURL-6104720
- https://snyk.io/vuln/SNYK-ALPINE318-CURL-6104720
- https://snyk.io/vuln/SNYK-ALPINE318-CURL-6104721
- https://snyk.io/vuln/SNYK-ALPINE318-CURL-6104721

Author: snyk-bot

images/main/alpine/Dockerfile

@@ -29,7 +29,7 @@ RUN set -ex; \
 
 
 # Once application has been built, prepare production image
-FROM nginx:alpine
+FROM nginx:1.25.3-alpine3.18
 
 ENV LANG=en_US.UTF-8 \
     LC_ALL=C.UTF-8