PackageJson: Fix key type for DependencyOverrides (#1307)

Co-authored-by: Som Shekhar Mukherjee <iamssmkhrj@gmail.com>

Author: electrovir

source/package-json.d.ts

@@ -212,7 +212,7 @@ export namespace PackageJson {
 	Recursive map describing selective dependency version overrides supported by npm.
 	*/
 	type DependencyOverrides = {
-		[packageName: string]: string | undefined | DependencyOverrides;
+		[packageName in string]: string | undefined | DependencyOverrides;
 	};
 
 	/**

test-d/package-json.ts

@@ -36,12 +36,14 @@ expectType<PackageJson.Dependency | undefined>(packageJson.peerDependencies);
 expectType<string[] | undefined>(packageJson.bundleDependencies);
 expectType<string[] | undefined>(packageJson.bundledDependencies);
 expectType<PackageJson.Dependency | undefined>(packageJson.resolutions);
+expectType<keyof PackageJson.Dependency>({} as string);
 expectType<PackageJson.WorkspaceConfig | string[] | undefined>(packageJson.workspaces);
 expectAssignable<PackageJson['overrides']>({foo: '1.0.0'});
 expectAssignable<PackageJson['overrides']>({foo: {'.': '1.0.0', bar: '1.0.0'}});
 expectAssignable<PackageJson['overrides']>({baz: {bar: {foo: '1.0.0'}}});
 expectAssignable<PackageJson['overrides']>({foo: undefined});
 expectAssignable<PackageJson['overrides']>({foo: {bar: undefined}});
+expectType<keyof PackageJson.DependencyOverrides>({} as string);
 expectAssignable<PackageJson.DevEngineDependency>({
 	name: 'unicorn',
 	version: '>= 1.0.0',