fix(gh-pages): build dir is now 'dist', add yarn caching and nvmrc

[bsmth]

Some changes breaking GitHub pages deploy after #97

failing builds:

• https://github.com/mdn/todo-react/actions/workflows/deploy.yml

Logs:

Run actions/upload-pages-artifact@v3
  with:
    path: build
    name: github-pages
    retention-days: 1
  env:
    GITHUB_PAGES: true
Run tar \
  tar \
    --dereference --hard-dereference \
    --directory "$INPUT_PATH" \
    -cvf "$RUNNER_TEMP/artifact.tar" \
    --exclude=.git \
    --exclude=.github \
    .
  shell: /usr/bin/sh -e {0}
  env:
    GITHUB_PAGES: true
    INPUT_PATH: build
tar: build: Cannot open: No such file or directory
tar: Error is not recoverable: exiting now
Error: Process completed with exit code 2.

[chrisdavidmills]

LGTM

[bsmth]

Thank you!