1.35.2

This release:

• Include windows.h (lowercase) to fix cross-compiled MinGW builds (#75, thanks @salman-javed-nz)
• Refine comment in last commit, 24ebadc (thanks @mbeutel)
• Cast char to signed to avoid type-limits warning (courtesy gsl-lite issue 337, PR 338)
• Change value used with *_CPP20_OR_GREATER to 202002L (nonstd-lite-project issue 60); Now, designate C++23 as speculative.
• Remove Travis CI configuration file (#74, thanks @striezel)
• Add workflow for GitHub Actions (thanks @striezel #73)
• Fix some typos (#72, thanks @striezel)
• Add parentheses around macro arguments (PVS-Studio: V1003)