Show libscterm version

tests/src/main.cpp

@@ -145,6 +145,7 @@ void show_truecolor(const sc::term& t) {
 
 int main() {
     try {
+        std::cout << "using " << libscterm_version() << '\n';
         sc::term term {STDERR_FILENO};
         show_rows_cols(term);
         show_grayscale_bar();