tests use -std=c++20

Author: vinniefalco

source/tests/SingleFile.hpp

@@ -33,6 +33,7 @@ class SingleFile
     {
         std::vector<std::string> cmds;
         cmds.emplace_back("clang");
+        cmds.emplace_back("-std=c++20");
         cmds.emplace_back(file);
         cc_.emplace_back(
             dir,