chore: pin two development dependencies to fix developer build

[shadowspawn]

This is a low-churn fix for developer build.

• pin rollup-plugin-ts because it dropped node 14 in a minor version (3.2.0 should have been 4.0.0 wessberg/rollup-plugin-ts#202)
• pin typescript because later versions of 4.x get an error during rollup (not sure where fault lies)

[!] (plugin Typescript) Error: Debug Failure. Unhandled SyntaxKind: Unknown.
Error: Debug Failure. Unhandled SyntaxKind: Unknown.

Fixes: #470

See also: #475

(The high-churn PR is #471 which drops rollup-plugin-ts and bumps minimum node version.)

[jettdc]

Any update on this and the related dev build workflows? Is this repository still being maintained? I'd love to contribute to this project but I'm not sure what the status of it is

[shadowspawn]

Any update on this and the related dev build workflows?

No.

By related workflows, do you mean the Renovate PRs? I admit have been ignoring those, but I suspect I can approve them!

Is this repository still being maintained?

Somewhat in limbo. Primary maintainer is busy elsewhere, and I am choosing to focus on responding to issues rather than coding while I get a feel for the repo and issues.

I'd love to contribute to this project but I'm not sure what the status of it is

Do you have ideas on what you want to contribute? I would warn that this is a mature slow-moving repository.

Edit: actually, open an issue rather than discuss here. (Or might be #484 that you have in mind.)