[configcat] Update to version 2.0.0

[kp-cat]

• Changes comply with the maintainer guide
• SHA512s are updated for each updated download
• The "supports" clause reflects platforms that may be fixed by this new version
• Any fixed CI baseline entries are removed from that file.
• Any patches that are no longer applied are deleted from the port's directory.
• The version database is fixed by rerunning ./vcpkg x-add-version --all and committing the result.
• Only one version is added to each modified port's versions file.

[FrankXie05]

The error log from https://dev.azure.com/vcpkg/public/_build/results?buildId=86516&view=artifacts&pathAsName=false&type=publishedArtifacts:

/usr/include/c++/9/variant: In instantiation of ‘struct std::variant_size<const configcat::Value>’:
/usr/include/c++/9/variant:94:29:   required from ‘constexpr const size_t std::variant_size_v<const configcat::Value>’
/usr/include/c++/9/variant:1023:10:   required from ‘struct std::__detail::__variant::__gen_vtable<true, void, configcat::to_json(json&, const configcat::Value&)::<lambda(auto:23&&)>&&, const configcat::Value&>’
/usr/include/c++/9/variant:1647:23:   required from ‘constexpr decltype(auto) std::__do_visit(_Visitor&&, _Variants&& ...) [with bool __use_index = false; bool __same_return_types = true; _Visitor = configcat::to_json(json&, const configcat::Value&)::<lambda(auto:23&&)>; _Variants = {const configcat::Value&}]’
/usr/include/c++/9/variant:1663:24:   required from ‘constexpr decltype(auto) std::visit(_Visitor&&, _Variants&& ...) [with _Visitor = configcat::to_json(json&, const configcat::Value&)::<lambda(auto:23&&)>; _Variants = {const configcat::Value&}]’
/mnt/vcpkg-ci/buildtrees/configcat/src/v2.0.0-53ea2195ee.clean/src/config.cpp:59:48:   required from here
/usr/include/c++/9/variant:81:12: error: invalid use of incomplete type ‘struct std::variant_size<configcat::Value>’
   81 |     struct variant_size<const _Variant> : variant_size<_Variant> {};
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/9/variant:78:12: note: declaration of ‘struct std::variant_size<configcat::Value>’
   78 |     struct variant_size;
      |            ^~~~~~~~~~~~