Added nlohmann/json:v3.11.3 as a submodule in ext-src and passed its path into the mscclpp build to avoid downloading the package at build time. (#1330)

[ROCm/rccl commit: b3b0ffdbf3]
2024-09-11 16:54:26 -06:00
@@ -2,3 +2,7 @@
 	path = ext-src/mscclpp
 	url = https://github.com/microsoft/mscclpp.git
 	ignore = dirty
+[submodule "ext-src/json"]
+	path = ext-src/json
+	url = https://github.com/nlohmann/json.git
+	ignore = dirty