gopeed: add update script

pkgs/by-name/go/gopeed/package.nix

···
     install -Dm644 assets/icon/icon_1024.png $out/share/icons/hicolor/1024x1024/apps/com.gopeed.Gopeed.png
   '';
 
+  passthru.updateScript = ./update.sh;
+
   meta = metaCommon // {
     mainProgram = "gopeed";
   };

pkgs/by-name/go/gopeed/update.sh

···
+#!/usr/bin/env nix-shell
+#!nix-shell -I nixpkgs=./. -i bash -p curl gnused jq yq nix bash coreutils nix-update
+
+set -eou pipefail
+
+ROOT="$(dirname "$(readlink -f "$0")")"
+
+latestTag=$(curl ${GITHUB_TOKEN:+-u ":$GITHUB_TOKEN"} -sL https://api.github.com/repos/GopeedLab/gopeed/releases/latest | jq --raw-output .tag_name)
+latestVersion=$(echo "$latestTag" | sed 's/^v//')
+
+currentVersion=$(nix-instantiate --eval -E "with import ./. {}; gopeed.version or (lib.getVersion gopeed)" | tr -d '"')
+
+if [[ "$currentVersion" == "$latestVersion" ]]; then
+    echo "package is up-to-date: $currentVersion"
+    exit 0
+fi
+
+nix-update gopeed.libgopeed
+
+curl https://raw.githubusercontent.com/GopeedLab/gopeed/${latestTag}/ui/flutter/pubspec.lock | yq . >$ROOT/pubspec.lock.json