CLI11 v2.1.2 Release Notes

    • 👉 Use main for the main branch of the repository #657
    • 🛠 Bugfix(cmake): Enforce at least C++11 when using CMake target #656
    • 🏗 Build: Don't run doxygen and CTest includes if a submodule #656
    • 🏗 Build: Avoid a warning on CMake 3.22 #656
    • 🏗 Build: Support compiling the tests with an external copy of Catch2 #653