ttconv 1.1.2

What's Changed

• VTT reader: fix empty line detection by @palemieux in #440
• Fix VTT reader timestamp tag bug by @palemieux in #445
• IMSC reader: tolerate some bad time expressions by @palemieux in #447
• Fix SCC timestamp alignment by @palemieux in #455

Full Changelog: 1.1.1...1.1.2

Deployed at https://pypi.org/project/ttconv/1.1.2/