Add config submodule

Bug: 589
Change-Id: I3c72db9f09752ef136c78468a5b18e93af9f45f9
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/78561
Reviewed-by: Ted Pudlik <tpudlik@google.com>
Commit-Queue: Rob Mohr <mohrr@google.com>
diff --git a/.gitmodules b/.gitmodules
index 661da01..dcaa5dd 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -22,3 +22,7 @@
 	path = third_party/freertos/Source
 	url = https://pigweed.googlesource.com/third_party/github/FreeRTOS/FreeRTOS-Kernel.git
 	branch = main
+[submodule "infra/config"]
+	path = infra/config
+	url = https://pigweed.googlesource.com/infra/config
+	branch = main