Revert "Update ExtUtils-MakeMaker to CPAN version 7.00"

This reverts commit 7b01e4b183c6629065260ae2befad5e5d4ab6b94.

The newest ExtUtils::MakeMaker uses the :utf8 layers, which is not
available under miniperl on Windows.  So the build fails.

Revert this for now until a fixed version is released.