chore(deps): update to TypeScript 4.5

TS variance check finally solved! 🎅

```ts
// Error below: Property 'foo' is missing in type '{}' but required in type '{ foo: string; }
const fooInjector: Injector<{ foo: string }> = createInjector();
```

closes #20

.github/workflows/ci.yml

@@ -15,8 +15,8 @@ jobs:
             matrix:
                 node-version: [12.x, 16.x]
         steps:
-            - uses: actions/checkout@v1
-            - uses: actions/setup-node@v1
+            - uses: actions/checkout@v2
+            - uses: actions/setup-node@v2
               with:
                 node-version: ${{ matrix.node-version }}
             - run: npm ci

README.md

@@ -46,7 +46,7 @@ yarn add typed-inject
 
 _Note: this package uses advanced TypeScript features. Only TS 3.0 and above is supported!_
 
-_Note: due to a [bug since TypeScript 3.8](https://github.com/microsoft/TypeScript/issues/37400) there is a small chance that the compiler [doesn't catch all errors](https://github.com/nicojs/typed-inject/issues/20) (as well as you might experience some performance issues)._
+_Note: due to a [bug in TypeScript >3.8 <4.5](https://github.com/microsoft/TypeScript/issues/37400) there is a small chance that the compiler [doesn't catch all errors](https://github.com/nicojs/typed-inject/issues/20) (as well as you might experience some performance issues)._
 
 _Note: projects must enable [`--strictFunctionTypes`](https://www.typescriptlang.org/tsconfig#strictFunctionTypes) (or `--strict`) in their Typescript config or some type errors may not be caught._