chore: alpine version `3.15.2`

Dockerfile

@@ -1,17 +1,17 @@
-FROM alpine as iconv
+FROM alpine:3.15.2 as iconv
 COPY ./conf/docker/iconv.sh /
 RUN sh /iconv.sh
 
-FROM alpine as vlmcsd
+FROM alpine:3.15.2 as vlmcsd
 COPY ./conf/docker/vlmcsd.sh /
 RUN sh /vlmcsd.sh
 
-FROM alpine
+FROM alpine:3.15.2
 LABEL maintainer="dnomd343"
 COPY . /var/www/kms-server
 COPY --from=iconv /tmp/iconv/ /usr/local/lib/
 COPY --from=vlmcsd /tmp/vlmcsd/ /usr/bin/
-RUN apk --update add --no-cache nginx curl php7 php7-fpm php7-json php7-iconv php7-sqlite3 && \
+RUN apk add --no-cache nginx curl php7 php7-fpm php7-json php7-iconv php7-sqlite3 && \
     rm /usr/lib/php7/modules/iconv.so && ln -s /usr/local/lib/iconv.so /usr/lib/php7/modules/ && \
     mv /usr/local/lib/libiconv.so /usr/local/lib/libiconv.so.2 && \
     mkdir -p /run/nginx && touch /run/nginx/nginx.pid && \