fix: Use gomplate from maintained base image

Fixes usage of outdated gomplate build

Fixes #13

Author: PSanetra

Dockerfile

@@ -1,5 +1,5 @@
 ARG NGINX_TAG
-FROM hairyhenderson/gomplate:v3 as gomplate
+FROM ghcr.io/hairyhenderson/gomplate:stable as gomplate
 FROM nginxinc/nginx-unprivileged:${NGINX_TAG} as single-page-app-server
 COPY --from=gomplate /gomplate /usr/local/bin/gomplate