build(cmake): mp-units-config.cmake file added with explicit dependencies

Addresses some of the issues mentioned in #156.

test_package/conanfile.py

@@ -25,7 +25,7 @@ import os
 
 class TestPackageConan(ConanFile):
     settings = "os", "compiler", "build_type", "arch"
-    generators = "cmake"
+    generators = "cmake", "cmake_find_package"
     
     def build(self):
         cmake = CMake(self)