Added package diagram generation from C++20 modules (#101)

tests/t30012/src/t30012_mod.cppm

@@ -0,0 +1,11 @@
+export module t30012.app;
+export import t30012.app.lib1;
+export import t30012.app.lib2;
+
+export namespace clanguml::t30012 {
+class A {
+    int get() { return a; }
+
+    int a;
+};
+}