replace command syntax with usage of file provider to set skip verify of self signed certs

.env.sample

@@ -147,3 +147,7 @@ COMPOSE_FILE="compose.yml"
 # NOTE(3wc): as of 2024-04-01 only the `icecast` recipe uses this
 #COMPOSE_FILE="$COMPOSE_FILE:compose.web-alt.yml"
 #WEB_ALT_ENABLED=1
+
+## Zulip
+#COMPOSE_FILE="$COMPOSE_FILE:compose.zulip.yml"
+#ZULIP_HTTPS_PROXY_ENABLED=1

compose.zulip.yml

@@ -0,0 +1,6 @@
+version: "3.8"
+services:
+  app:
+    deploy:
+      labels:
+        - "traefik.http.services.${STACK_NAME}.loadBalancer.serversTransport=zulip@file"

file-provider.yml.tmpl

@@ -1,5 +1,10 @@
 ---
 http:
+    {{ if eq (env "ZULIP_HTTPS_PROXY_ENABLED") "1" }}
+  serversTransports:
+    zulip:
+      insecureSkipVerify: true
+  {{ end }}
   middlewares:
     {{ if eq (env "KEYCLOAK_MIDDLEWARE_ENABLED") "1" }}
     keycloak: