Add --browse flag to evergreen patch

Some CLI clients for websites (such as [hub](https://github.com/github/hub)) add a --browse flag to certain commands so you can easily open the created object in your browser. The evergreen patch command should also support this since without it users either have to click or use hacky scripts like:

output=$(evergreen patch --yes --finalize $@)

    ec=$?

    echo "${output}"

    if [[ $ec != 0 ]]; then echo "Evergreen patch failed." && return $ec; fi

    url=$(echo "${output}" | grep "Build" | grep -o -e "https:\/\/.*")

    python -m webbrowser "$url"