I have a very simple library with the following dtructure:

src
 - myLib.h
 - myLib.cpp
App
 - testApp.cpp
CMakelist.txt

cmake_minimum_required(VERSION 3.10)
project(Testing)


# JSON
find_package(nlohmann_json REQUIRED)


add_library(myLib SHARED
        src/myLib.cpp
)

target_link_libraries(myLib PUBLIC nlohmann_json::nlohmann_json)


set(CMAKE_BUILD_TYPE debug)


install(TARGETS myLib 
        LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR})
install(DIRECTORY src/ DESTINATION include FILES_MATCHING PATTERN "*.h")

Building the library works fine but when I link with testApp.cpp, which just includes myLib.h, I get the following errors:

g++ testApp.cpp -o runApp -I ../install/include/ -l ../install/lib/libmyLib.so

./install/include/myLib.h:16:10: fatal error: nlohmann/json.hpp: No such file or directory
   16 | #include <nlohmann/json.hpp>

What could be going wrong here?