Switch to @rollup/plugin-typescript from rollup-plugin-typescript2

[pravi]

Similar to weiran-zsd/dts-cli#2

[rschristian]

I'm going to close this out as it's not an actual issue.

There may be beneficial reasons to switch, I have no idea, but with the only provided justification being the following:

as it is maintained by rollup community directly has better chance of long term maintenance.

...I don't see that as being particularly compelling. rollup-plugin-typescript2 does (mostly) fill our needs and is still being actively maintained.