[PATCH] doc: environment: Fix typo

[Bin Meng]

On Wed, May 25, 2022 at 9:09 AM Chris Packham <judge.packham at gmail.com> wrote:
>
> "valu" should be "value".
>
> Signed-off-by: Chris Packham <judge.packham at gmail.com>
> ---
>
>  doc/usage/environment.rst | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>

Reviewed-by: Bin Meng <bmeng.cn at gmail.com>