Add support for newer plugin-node-resolve versions

Due to [0] in plugin-node-resolve, it changes the way modules are
resolved. It now looks at package.json and figures it out from
there although if the stuff it is looking for is not found
it falls back to how it did the resolving in older versions.
Unfortunately there is no config to force the behaviour
so we have to use the new behaviour.

This is what it looks like:

```
  "exports": {
    ".": {
      "development": "./development/reactive-element.js",
      "default": "./reactive-element.js"
    },
    ....
    "./decorators.js": {
      "development": "./development/decorators.js",
      "default": "./decorators.js"
    },
    ....
  },
```

Thus "./decorators" fails to match "./decorators.js" and so it fails
to resolve.


[0] https://github.com/rollup/plugins/commit/3d60158f21e0b6a5a8a53d9977928e2e148cb885

Change-Id: I7829591e45662ee6028182beb57396b327823275
diff --git a/web/gr-delete-repo.ts b/web/gr-delete-repo.ts
index 5a2ece1..55995fd 100644
--- a/web/gr-delete-repo.ts
+++ b/web/gr-delete-repo.ts
@@ -21,7 +21,7 @@
   RepoName,
 } from '@gerritcodereview/typescript-api/rest-api';
 import {css, html, LitElement} from 'lit';
-import {customElement, property, query, state} from 'lit/decorators';
+import {customElement, property, query, state} from 'lit/decorators.js';
 
 // TODO: This should be defined and exposed by @gerritcodereview/typescript-api
 type GrOverlay = Element & {
diff --git a/web/test/test-setup.ts b/web/test/test-setup.ts
index ddeaf89..2196ebc 100644
--- a/web/test/test-setup.ts
+++ b/web/test/test-setup.ts
@@ -14,7 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import 'chai/chai';
+import 'chai/chai.js';
 import '@gerritcodereview/typescript-api/gerrit';
 import {css} from 'lit';