[Development] Utf8 as the 8bit encoding on Windows

[Tony Sarajärvi]

>>Requiring that Windows version is, unfortunately, not yet acceptable. Many corporations, Intel included, have a slow Windows upgrade cycle. According to the WIkipedia page[1], MSFT is offering a 2½-year support cycle for each of those Windows 10 releases, so we need to support pre-1903 releases until at least May 11, 2021. That's past the Qt 6 release date.

The CI tends to always update to the latest Windows available, just as we upgrade to the latest Ubuntu or macOS when available. But what Qt supports is another thing. In 90% of conversations I have, they are mixed together as the same thing.

Looking at the Qt documentation, it says that Qt supports any generic Linux with GCC 5 or later: https://code.qt.io/cgit/qt/qtdoc.git/tree/doc/src/platforms/supported-platforms.qdocinc?h=5.15#n54

The same document also says that Qt supports Windows 10 without mentioning the build numbers.

Unless the wording in that document is changed, it means that Qt supports all older versions of Windows 10 as well and any Linux distro, as long as it has GCC 5, but we just don't have them in the CI.

-T