Improved Nginx Dockerfile

images/nginx/1.18/Dockerfile

@@ -15,7 +15,7 @@ RUN mkdir /etc/nginx/certs \
   && echo -e "\n\n\n\n\n\n\n" | openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout /etc/nginx/certs/nginx.key -out /etc/nginx/certs/nginx.crt
 
 ARG TARGETARCH
-ENV TARGETARCH=${TARGETARCH:-amd64}
+
 RUN ( \
   cd /usr/local/bin/ \
   && curl -L https://github.com/FiloSottile/mkcert/releases/download/v1.4.3/mkcert-v1.4.3-linux-$TARGETARCH -o mkcert \