Update Dockerfile to work with other version of nginx

Author: rptmat57

modules/Dockerfile.alpine

@@ -1,4 +1,5 @@
-FROM nginx:mainline-alpine as builder
+ARG NGINX_VERSION_FROM=mainline-alpine
+FROM nginx:${NGINX_VERSION_FROM}-alpine as builder
 
 ARG ENABLED_MODULES
 
@@ -60,7 +61,7 @@ RUN set -ex \
     done \
     && echo "BUILT_MODULES=\"$BUILT_MODULES\"" > /tmp/packages/modules.env
 
-FROM nginx:mainline-alpine
+FROM nginx:${NGINX_VERSION_FROM}-alpine
 COPY --from=builder /tmp/packages /tmp/packages
 RUN set -ex \
     && . /tmp/packages/modules.env \