feat: serve default robots txt

.env.sample

@@ -184,3 +184,4 @@ COMPOSE_FILE="compose.yml"
 #ANUBIS_OG_PASSTHROUGH=true
 #ANUBIS_OG_EXPIRY_TIME=1h
 #ANUBIS_OG_CACHE_CONSIDER_HOST=true
+#ANUBIS_SERVE_ROBOTS_TXT=true

compose.anubis.yml

@@ -16,6 +16,7 @@ services:
       OG_PASSTHROUGH: "${ANUBIS_OG_PASSTHROUGH}"
       OG_EXPIRY_TIME: "${ANUBIS_OG_EXPIRY_TIME}"
       OG_CACHE_CONSIDER_HOST: "${ANUBIS_OG_CACHE_CONSIDER_HOST}"
+      SERVE_ROBOTS_TXT: "${ANUBIS_SERVE_ROBOTS_TXT}"
     networks:
     - proxy
     deploy: