fix: incorrect return type when using union types as Res or Req in defineInvoke

[sumimakito]

As in TypeScript, Conditional Types are distributive¹, this means when:

const context = createContext()
const invokeEventa = defineInvokeEventa<C, A | B>()
const invoke = defineInvoke(context, invokeEventa)

… invoke is of type ((req: A, invokeRequest?: unknown) => Promise<C> | (req: B, invokeRequest?: unknown) => Promise<C>), which is unwanted. The expected type should be (req: A | B, invokeRequest?: unknown) => Promise<C>. The fix wraps the type into [T] to avoid this behavior.

This pull request also adds the missing @vitest/coverage-v8 dependency and excludes semver@6.3.1 from trustPolicy. As pnpm does not like the comments in the YAML², I will write the reason here: electron@39.2.6 (latest ATM) depends on @electron/get@2.0.3 (^2.0.0) which dependes on semver@6.3.1 (^6.2.0).

Footnotes

1. https://www.typescriptlang.org/docs/handbook/2/conditional-types.html#distributive-conditional-types ↩

2. https://github.com/pnpm/pnpm/issues/2008 ↩