add missing lib

lib/ArduinoJson/test/JsonBuffer/CMakeLists.txt

@@ -0,0 +1,14 @@
+# ArduinoJson - arduinojson.org
+# Copyright Benoit Blanchon 2014-2018
+# MIT License
+
+add_executable(JsonBufferTests
+	nested.cpp
+	nestingLimit.cpp
+	parse.cpp
+	parseArray.cpp
+	parseObject.cpp
+)
+
+target_link_libraries(JsonBufferTests catch)
+add_test(JsonBuffer JsonBufferTests)