add missing lib

lib/ArduinoJson/test/Polyfills/CMakeLists.txt

@@ -0,0 +1,13 @@
+# ArduinoJson - arduinojson.org
+# Copyright Benoit Blanchon 2014-2018
+# MIT License
+
+add_executable(PolyfillsTests 
+	isFloat.cpp
+	isInteger.cpp
+	parseFloat.cpp
+	parseInteger.cpp
+)
+
+target_link_libraries(PolyfillsTests catch)
+add_test(Polyfills PolyfillsTests)