Stepping down as Qt 6 maintainers

After quite some time maintaining Qt in Debian both Dmitry Shachnev and I decided to not maintain Qt 6 when it's published (expected in December 2020, see https://wiki.qt.io/Qt_6.0_Release). We will do our best to keep the Qt 5 codebase up and running.

We **love** Qt, but it's a huge codebase and requires time and build power, both things that we are currently lacking, so we decided it's time for us to step down and pass the torch. And a new major version seems the right point to do that.

We will be happy to review and/or sponsor other people's work or even occasionally do uploads, but we can't promise to do it regularly.

Some things we think potential Qt 6 maintainers should be familiar with are, of course, C++ packaging (specially symbols files) and CMake, as Qt 6 will be built with it.

We also encourage prospective maintainers to remove the source's -everywhere-src suffixes and just keep the base names as source package names: qtbase6, qtdeclarative6, etc.

It has been an interesting ride all these years, we really hope you enjoyed using Qt.

Thanks for everything,

Dmitry and Lisandro.

Note 20200818 12:12 ARST: I was asked if the move has anything to do with code quality or licensing. The answer is a huge no, Qt is a **great** project which we love. As stated before it's mostly about lack of free time to properly maintain it.