Orchid is being re-licensed from LGPL to GPL for 1.0.0 release

[cjbrooks12]

I discovered that Orchid depends on a GPL library (PlantUML) which is a violation of GPL when Orchid is licensed under LGPL. The easiest remedy is to change Orchid's license to be in compliance, adopting the viral GPL-3.0 license for itself. This change will go into effect starting from version 1.0.0.

I will accept a contribution to change the PlantUML dependency to its LGPL distribution until the end of this year. From 2022 onward, if I have not received any contributions that would allow Orchid to remain under LGPL, the change to GPL will be permanent and I may start using other GPL libraries as dependencies of Orchid.

See #405 for full context and alternatives considered.