* remove most net452 related code
* first net4 remove
* migrate test proj to net5 base
* fix format
* update sta xunit to fix platform not support
* Squashed commit of the following:
commit 16e1f819058ad281e1571b356c10d4d6ce77cf38
Author: Boshi Lian <farmer1992@gmail.com>
Date: Tue Dec 8 22:42:57 2020 -0800
temp disable some version converter
commit 7d1a651f4e7d27d1e61c91f46f73ac8d04ea8ab9
Author: Boshi Lian <farmer1992@gmail.com>
Date: Tue Dec 8 20:55:44 2020 -0800
add missing watcher generator files
commit 3f3199aad269bf89406ea71d0bc63f1a7ec23245
Author: Boshi Lian <farmer1992@gmail.com>
Date: Tue Dec 8 22:14:47 2020 +0000
gen v1.20.0
* bump version to 4.0
* support empty spec
* fix version converter for generator
* add generated header
* fix warning
* rerun generator
c0e96f516b