new: [compose] propagate ``$PROJECT_NAME``

bin/compose

@@ -1021,6 +1021,9 @@ load_env() {
         fi
         docker_run_opts+=("-e" "ALL_RELATIONS=$NEW_ALL_RELATIONS")
     fi
+    if [ -n "$PROJECT_NAME" ]; then
+        docker_run_opts+=("-e" "PROJECT_NAME=$PROJECT_NAME")
+    fi
 
 }
 
@@ -1035,9 +1038,11 @@ show_env() {
     echo "  COMPOSE_LAUNCHER_CACHE: $COMPOSE_LAUNCHER_CACHE"
     echo "  SESSION_DIR: $SESSION_DIR"
     echo "  TZ_PATH: $TZ_PATH"
-    if [ -n "$ALL_RELATIONS" ]; then
+    [ -n "$ALL_RELATIONS" ] &&
         echo "  ALL_RELATIONS: $ALL_RELATIONS"
-    fi
+    [ -n "$PROJECT_NAME" ] &&
+        echo "  PROJECT_NAME: $PROJECT_NAME"
+
 }