Add C++20

alvokanto/src/language.rs

@@ -88,6 +88,10 @@ pub fn get_supported_languages() -> HashMap<String, LanguageParams> {
     }
 
     let mut languages = HashMap::new();
+    languages.insert(
+        "cpp.20.g++".into(),
+        build_gcc_params(2, "GNU G++20 {}", "/usr/bin/g++".into(), "c++", "c++20"),
+    );
     languages.insert(
         "cpp.17.g++".into(),
         build_gcc_params(2, "GNU G++17 {}", "/usr/bin/g++".into(), "c++", "c++17"),