0.6.0

Release 0.6.0 of expected lite contains the following changes.

Additions:

• Enable importing cmake targets from the build tree (#39, thanks @fbdtemme).
• Add script tc-cl.bat. See also nonstd-lite-project issues 54.
• Add nsel_CONFIG_NO_EXCEPTIONS_SEH configuration flag.
• Update script and test for compilation without exceptions.
• Add example/03-no-exceptions.cpp.
• Introduce GitHub Actions CI.

Changes:

• std::expected appears in C++23, not C++20 (#43, thanks @bigerl).
• Allow to move-assign from move-only unexpected (#40).
• Avoid warning -Wundef for _MSC_VER.
• Change to use SEH at default with MSVC for no C++ exception case.
• Replace _CPPUNWIND with _HAS_EXCEPTIONS (#27, thanks @DBJDBJ). See also nonstd-lite-project issue 48.
• Handle lest test framework as system include to prevent warnings, use autoregister.
• Update Readme guided by markdownlint.

Fixes:

• Fix r-value ref miscompile on MSVC v19.22 (#41, thanks @jacobly0).
• Fix concept checks in the assignment operators (#40, thanks @szaszm).