Run npm run demo to attempt to mimic the GitHub server. It's not perfect, but it's way easier than getting act set up.
You'll need to move demo/.secrets_EXAMPLE to demo/.secrets and add your API keys in there.
Once your updates are in master and you've tagged a new release, you'll also need to update the major version tag (e.g. v2) so it points to your changes. To do this, run the following commands (while on master):
# Retrieves latest tags from the repository
git fetch
# Updates the major version tag (v2) to point to v2.x.x
git tag -f -a v2 -m "v2.x.x"
# Pushes tags to repository
git push -f --tags