Add Cmake install and find_package support

README.md

@@ -30,7 +30,16 @@ The supported syntax can be found in the [definitions docs](docs/definitions.md)
 
 ## How to add maddy to your cmake project
 
-You can use [FetchContent](https://cmake.org/cmake/help/latest/module/FetchContent.html)
+Use `find_package()` which provides `maddy::maddy` target:
+
+```cmake
+find_package(maddy REQUIRED)
+
+add_executable(my_exe)
+target_link_libraries(my_exe PRIVATE maddy::maddy)
+```
+
+Or you can use [FetchContent](https://cmake.org/cmake/help/latest/module/FetchContent.html)
 which was introduced in CMake 3.11.
 
 This way you can add