Replace broken link with public repo

docs-ci flagged broken link that cannot be reached,
so point to the public repo file that has the
website data.

<https://github.com/nextstrain/cli/actions/runs/27976460860/job/82795368857>

Author: joverlee521

CHANGES.md

@@ -450,8 +450,8 @@ below.
 
 * Colorized and bolded output is disabled when stdout is not attached to a
   terminal (e.g. is redirected to a file, piped to another program, etc.) or
-  when the [`NO_COLOR` environment variable](https://no-color.org) is set to a
-  non-empty value.
+  when the [`NO_COLOR` environment variable](https://github.com/jcs/no_color/blob/@/index.md)
+  is set to a non-empty value.
   ([#419][])
 
 * The readability of `--help` output is improved by the addition of blank lines