added type to shut ts compiler up

Author: JohnstonCode

src/types/testrunner.d.ts

@@ -0,0 +1,8 @@
+interface testrunnerconfig {
+  ui: string;
+  useColors: boolean;
+}
+
+declare module "vscode/lib/testrunner" {
+  function configure(config: testrunnerconfig): void;
+}