fix(deno): update types for deno ^1.4.0

In version 1.4 Deno adopted;

- the tsconfig setting [importsNotUsedAsValues](https://www.typescriptlang.org/tsconfig#importsNotUsedAsValues) - denoland/deno#7413
- the tsconfig setting [isolatedModules](https://www.typescriptlang.org/tsconfig#isolatedModules) when using the deno `--unstable` flag - denoland/deno#7326 ([intended to be enabled by default in 1.5](denoland/deno#7326))

These require the use of;
- type only imports for values which are only used as types (`importsNotUsedAsValues`)
- type only exports for types which are re-exported (`isolatedModules`)

deno.ts

@@ -1,7 +1,7 @@
 // Bootstrap yargs for Deno platform:
 import denoPlatformShim from './lib/platform-shims/deno.ts'
 import { YargsWithShim } from './build/lib/yargs-factory.js'
-import { YargsInstance as YargsType } from './build/lib/yargs-factory.d.ts'
+import type { YargsInstance as YargsType } from './build/lib/yargs-factory.d.ts'
 
 const WrappedYargs = YargsWithShim(denoPlatformShim)
 

types.ts

@@ -1,7 +1,7 @@
 // expose types for the benefit of Deno.
-import { YargsInstance as YargsType, Arguments } from './build/lib/yargs-factory.d.ts'
+import type { YargsInstance as YargsType, Arguments } from './build/lib/yargs-factory.d.ts'
 
-export {
+export type {
   Arguments,
   YargsType
 }