Fix the Step 3 YAML code block to upload linter artifacts (#50)

* Add reporter to markdown lint step

* Update Step 3 instructions accordingly

.github/steps/3-upload-test-reports.md

@@ -15,7 +15,8 @@ To upload artifacts to the artifact storage, we can use an action built by GitHu
 ### :keyboard: Activity: Upload test reports
 
 1. Edit your workflow file.
-1. Add a step to your `build` job that uses the `upload-artifacts` action.
+1. Update the `Run markdown lint` step in your `build` job to use `vfile-reporter-json` and output the results to `remark-lint-report.json`.
+1. Add a step to your `build` job that uses the `upload-artifact` action. This step should upload the `remark-lint-report.json` file generated by the updated `Run markdown lint` step.
 
    ```yml
    build:
@@ -25,13 +26,13 @@ To upload artifacts to the artifact storage, we can use an action built by GitHu
 
        - name: Run markdown lint
          run: |
-           npm install remark-cli remark-preset-lint-consistent
-           npx remark . --use remark-preset-lint-consistent --frail
+           npm install remark-cli remark-preset-lint-consistent vfile-reporter-json
+           npx remark . --use remark-preset-lint-consistent --report vfile-reporter-json 2> remark-lint-report.json
 
        - uses: actions/upload-artifact@v3
          with:
            name: remark-lint-report
-           path: public/
+           path: remark-lint-report.json
    ```
 
 1. Commit your change to this branch.