File README.packager of Package bat

# Heavily based on https://build.opensuse.org/package/view_file/devel:languages:rust/racer/README.packager (Thank you for this!)
#
# Generating `vendor.tar.xz`

1. Install `cargo` from official repositories.

    zypper install cargo

2. Checkout version

    git clone https://github.com/sharkdp/bat ~/tmp/bat
    cd ~/tmp/bat
    git checkout v0.10.0 (or another version from `git tag --list`)

3. Generate archive

    cargo vendor
    tar -cJf vendor.tar.xz vendor