ci: use RUNNER_TEMP

Author: hi-ogawa

packages/plugin-rsc/e2e/basic.test.ts

@@ -111,7 +111,12 @@ test.describe.only(() => {
   // disabled by default
   // if (process.env.TEST_ISOLATED !== 'true') return
 
-  let tmpRoot = path.join(os.tmpdir(), 'test-vite-rsc')
+  // RUNNER_TEMP is for Github Actions
+  // https://github.com/actions/toolkit/issues/518
+  const tmpRoot = path.join(
+    process.env['RUNNER_TEMP'] || os.tmpdir(),
+    'test-vite-rsc',
+  )
   test.beforeAll(async () => {
     console.error('[beforeAll]')
     await setupIsolatedFixture({ src: 'examples/basic', dest: tmpRoot })