add missing lib

lib/ArduinoJson/scripts/travis/coverage.sh

@@ -0,0 +1,10 @@
+#!/bin/sh -eux
+
+curl https://cmake.org/files/v3.4/cmake-3.4.0-Linux-x86_64.tar.gz | tar xz -C /tmp --strip 1
+
+/tmp/bin/cmake -DCOVERAGE=true .
+make 
+make test
+
+pip install --user cpp-coveralls 'requests[security]'
+coveralls --exclude third-party --gcov-options '\-lp'; fi