* ⬆️ Doctest 2.4.7
* 👷 add CI step for ICPC
* 👷 add CI step for ICPC
* 👷 add CI step for ICPC
* ⬇️ downgrade to Doctest 2.4.6
* 👷 add CI step for ICPC
* 👷 add CI step for ICPC
* 👷 add CI step for ICPC
* 👷 add CI step for ICPC
* 👷 add CI step for ICPC
* 🔇 suppress warning #2196: routine is both "inline" and "noinline"
* Re-enable <filesystem> detection on ICPC
* Limit regression test for #3070 to Clang and GCC >=8.4
* Disable deprecation warnings on ICPC
* Disable regression test for #1647 on ICPC (C++20)
* Fix compilation failure of regression test for #3077 on ICPC
* Disable wstring unit test on ICPC
Fixes:
error 913: invalid multibyte character sequence
* Add ICPC to README
Co-authored-by: Niels Lohmann <mail@nlohmann.me>