add vitest for remark-growi-directive package

packages/remark-growi-directive/vitest.config.ts

@@ -0,0 +1,13 @@
+import tsconfigPaths from 'vite-tsconfig-paths';
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  plugins: [
+    tsconfigPaths(),
+  ],
+  test: {
+    environment: 'node',
+    clearMocks: true,
+    globals: true,
+  },
+});