Fix alpine docker file (#10992)

<!--
if this PR closes one or more issues, you can automatically link the PR
with
them by using one of the [*linking
keywords*](https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue#linking-a-pull-request-to-an-issue-using-a-keyword),
e.g.
- this PR should close #xxxx
- fixes #xxxx

you can also mention related issues, PRs or discussions!
-->

# Description

Fix docker file. For more detail see:
https://github.com/nushell/nushell/issues/8307

docker/Dockerfile

@@ -15,7 +15,7 @@ RUN echo '/usr/bin/nu' >> /etc/shells \
     && cd /tmp \
     && wget -qO - https://api.github.com/repos/nushell/nushell/releases/latest \
     | grep browser_download_url \
-    |grep musl \
+    | grep musl.tar.gz \
     | cut -f4 -d '"' \
     | xargs -I{} wget {} \
     && tar -xzf nu* \