Update tutorials, drop python 3.6, add python 3.9, bump requirements

What's Changed

• Minor sync of CHANGELOG.rst by @asanin-epfl in #145
• Add authors by @mgeplf in #146
• Remove restriction pylint==2.4.4 by @joni-herttuainen in #147
• Updated the tutorials by @joni-herttuainen in #148
• Bump click requirement by @GianlucaFicarelli in #149
• Drop python3.6 support by @GianlucaFicarelli in #150
• Add python 3.9 tests and ensure int64 in reports by @GianlucaFicarelli in #151

Full Changelog: v0.13.0...v0.13.1