README.md: Note jq installation

"`jq` may be installed through your distribution's repository."

Test: N/A
Change-Id: I92e3209f9553c87aff29fd67056b8400fc99f471
diff --git a/json_module_graph/README.md b/json_module_graph/README.md
index 68ce5d5..f6d0f0a 100644
--- a/json_module_graph/README.md
+++ b/json_module_graph/README.md
@@ -1,6 +1,7 @@
 # JSON module graph queries
 
 This directory contains `jq` scripts that query Soong's module graph.
+`jq` may be installed through your distribution's repository.
 
 Usage: