fix: the example's path dependency follows the package rename

`dependency 'godot-cpp' resolved to package 'godot-cpp-m' (mismatch with
declared name 'godot-cpp')` -- examples/summator still asked for the old short
name. It is the only place that referred to the package by name.

Author: speak-agent

examples/summator/mcpp.toml

@@ -15,4 +15,4 @@ license     = "MIT"
 kind = "shared"
 
 [dependencies]
-godot-cpp = { path = "../.." }
+godot-cpp-m = { path = "../.." }