message: Add gltfpack installation instructions to main readme
diff: @@ -20,6 +20,19 @@ Alternatively you can [download the .zip archive from GitHub](https://github.com
  The library is available as a Linux package in some distributions ([ArchLinux](https://aur.archlinux.org/packages/meshoptimizer/)).
  +### Installing gltfpack
  +
  +`gltfpack` is a CLI tool for optimizing meshes using meshoptimizer.
  +
  +You can download a pre-built binary for gltfpack on Releases page, or install npm package as follows:
  +```
  +npm install -g gltfpack
  +```
  +
  +You can also find prebuilt binaries of `gltfpack` built from master by going to https://github.com/zeux/meshoptimizer/actions, opening the latest run, and downloading the artifact for your platform. It will give you a binary file you can place into your `$PATH`.
  +
  +[Learn more about gltfpack](./gltf/README.md)
  +
  ## Building
  meshoptimizer is distributed as a set of C++ source files. To include it into your project, you can use one of the two options:
  