fix: [small] fix to receive partial contents

[s-yoshika]

Context

When we use core/node package by sd-step with pkg-version option, we have an error like below.

13:03:58   $ sd-step exec --pkg-version "~6.11.0" core/node "node -v"
13:03:59   ERROR: Unable to access to Habitat depot API. Unexpected status code: 206
13:03:59   Trying to fetch versions from installed packages...
13:03:59   ERROR: Failed to get package version: The specified version not found

We use Habitat API to check the versions of packages in here, but the API returns different status codes in some cases.

It returns 200 code if the contents is full,
and it returns 206 code if the contents is left

$ curl https://willem.habitat.sh/v1/depot/pkgs/core/node?range=0 -I 2>/dev/null | head -n 1
HTTP/1.1 206 Partial Content
$ curl https://willem.habitat.sh/v1/depot/pkgs/core/node?range=50 -I 2>/dev/null | head -n 1
HTTP/1.1 200 OK

Objective

This PR allows sd-step to receive partial content.