changelogs: Fix count variable type

[pkratoch]

The variable count in print_changelogs used to be int32_t, but was changed to int64_t. Because of that, the build on i686 arch fails with:

error: conversion from 'int64_t' {aka 'long long int'} to
'__gnu_cxx::__normal_iterator<libdnf5::rpm::Changelog*,
std::vector<libdnf5::rpm::Changelog> >::difference_type' {aka 'int'} may
change value [-Werror=conversion]

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The issue blocks build on Fedora rawhide: https://koji.fedoraproject.org/koji/taskinfo?taskID=102735120

[jan-kolarik]

It looks it should work, also on i686. We are currently running CI only against x86_64 unfortunately. This could be probably improved.

Also one other thing. The libdnf5-cli are public headers. I am not sure if the changelogs.hpp header will be in the future also wrapped using SWIG. In that case we would need to get rid of the std::variant from the interface and I think it would be even better for readability, because it seems the logic there could be easily refactored to several overloads...

[jan-kolarik]

LGTM, created follow-up ticket for mentioned SWIG issue.