Use tar.xz instead of tar.gz

shellcheck v0.11.0 introduced `tar.gz` files. Previous releases exclusively use `tar.xz`.

Signed-off-by: Jason Garber <jason@sixtwothree.org>

Author: jgarber623

src/shellcheck/install.sh

@@ -16,6 +16,6 @@ $nanolayer_location \
     install \
     devcontainer-feature \
     "ghcr.io/devcontainers-extra/features/gh-release:1" \
-    --option repo='koalaman/shellcheck' --option binaryNames='shellcheck' --option version="$VERSION" --option assetRegex='shellcheck-.*.tar.gz$'
+    --option repo='koalaman/shellcheck' --option binaryNames='shellcheck' --option version="$VERSION" --option assetRegex='shellcheck-.*.tar.xz$'
 
 echo 'Done!'