archisteamfarm: fix update scripts, make easier to re-run ui update script

pkgs/by-name/ar/archisteamfarm/update.sh

@@ -22,5 +22,4 @@ fi
 
 $(nix-build -A archisteamfarm.fetch-deps --no-out-link)
 
-cd "$asf_path/web-ui"
-./update.sh
+"$asf_path/web-ui/update.sh"

pkgs/by-name/ar/archisteamfarm/web-ui/update.sh

@@ -1,15 +1,16 @@
 #!/usr/bin/env nix-shell
-#! nix-shell -I nixpkgs=../../../../.. -i bash -p curl gnused jq common-updater-scripts prefetch-npm-deps
+#! nix-shell -I nixpkgs=./. -i bash -p curl gnused jq common-updater-scripts prefetch-npm-deps
 set -eou pipefail
+cd "$(dirname "${BASH_SOURCE[0]}")"
 
-cd "$(dirname "$0")"/../../../../..
+cd ../../../../..
 version=$(nix-instantiate --strict --eval -A archisteamfarm.version | jq -r)
 cd -
 ui=$(curl ${GITHUB_TOKEN:+" -u \":$GITHUB_TOKEN\""} "https://api.github.com/repos/JustArchiNET/ArchiSteamFarm/contents/ASF-ui?ref=$version" | jq -r .sha)
 
 curl "https://raw.githubusercontent.com/JustArchiNET/ASF-ui/$ui/package-lock.json" -o package-lock.json
 
-cd -
+cd ../../../../..
 update-source-version archisteamfarm.ui "$ui"
 cd -