chore(deps-dev): bump @types/node from 15.3.1 to 15.6.0

Bumps [@types/node](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/node) from 15.3.1 to 15.6.0.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/node)

Signed-off-by: dependabot[bot] <support@github.com>

package-lock.json

@@ -1698,9 +1698,9 @@
       "dev": true
     },
     "@types/node": {
-      "version": "15.3.1",
-      "resolved": "https://registry.npmjs.org/@types/node/-/node-15.3.1.tgz",
-      "integrity": "sha512-weaeiP4UF4XgF++3rpQhpIJWsCTS4QJw5gvBhQu6cFIxTwyxWIe3xbnrY/o2lTCQ0lsdb8YIUDUvLR4Vuz5rbw==",
+      "version": "15.6.0",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-15.6.0.tgz",
+      "integrity": "sha512-gCYSfQpy+LYhOFTKAeE8BkyGqaxmlFxe+n4DKM6DR0wzw/HISUE/hAmkC/KT8Sw5PCJblqg062b3z9gucv3k0A==",
       "dev": true
     },
     "@types/normalize-package-data": {