gdevelop: added update script

pkgs/by-name/gd/gdevelop/darwin.nix

···
   pname,
   version,
   meta,
+  passthru,
 }:
 stdenvNoCC.mkDerivation (finalAttrs: {
-  inherit pname version meta;
+  inherit
+    pname
+    version
+    meta
+    passthru
+    ;
 
   src = fetchurl {
     url = "https://github.com/4ian/GDevelop/releases/download/v${version}/GDevelop-5-${version}-universal-mac.zip";

pkgs/by-name/gd/gdevelop/linux.nix

···
   version,
   pname,
   meta,
+  passthru,
 }:
 let
   src =
···
     version
     src
     meta
+    passthru
     ;
 
   extraInstallCommands = ''

pkgs/by-name/gd/gdevelop/package.nix

···
     mainProgram = "gdevelop";
     platforms = [ "x86_64-linux" ] ++ lib.platforms.darwin;
   };
+  passthru.updateScript = ./update.sh;
 in
 if stdenv.hostPlatform.isDarwin then
   callPackage ./darwin.nix {
···
       pname
       version
       meta
+      passthru
       ;
   }
 else
···
       pname
       version
       meta
+      passthru
       ;
   }

pkgs/by-name/gd/gdevelop/update.sh

···
+#!/usr/bin/env nix-shell
+#!nix-shell -i bash -p curl jq gnused
+
+set -euo pipefail
+
+cd "$(dirname "$0")" || exit 1
+
+# Grab latest version from the GitHub repository
+LATEST_VER="$(curl --fail -s ${GITHUB_TOKEN:+-u ":$GITHUB_TOKEN"} "https://api.github.com/repos/4ian/GDevelop/releases" | jq -r '.[0].tag_name' | sed 's/^v//')"
+CURRENT_VER="$(grep -oP 'version = "\K[^"]+' package.nix)"
+
+if [[ "$LATEST_VER" == "$CURRENT_VER" ]]; then
+    echo "gdevelop is up-to-date"
+    exit 0
+fi
+
+echo "Updating gdevelop from $CURRENT_VER to $LATEST_VER"
+
+# Update the version
+sed -i "s#version = \".*\";#version = \"$LATEST_VER\";#g" package.nix
+
+# Update hashes
+# - Linux
+
+LINUX_HASH="$(nix-hash --to-sri --type sha256 "$(nix-prefetch-url --type sha256 "https://github.com/4ian/GDevelop/releases/download/v${LATEST_VER}/GDevelop-5-${LATEST_VER}.AppImage")")"
+sed -i "s#hash = \".*\"#hash = \"$LINUX_HASH\"#g" linux.nix
+
+# - Darwin
+
+DARWIN_HASH="$(nix-hash --to-sri --type sha256 "$(nix-prefetch-url --type sha256 "https://github.com/4ian/GDevelop/releases/download/v${LATEST_VER}/GDevelop-5-${LATEST_VER}-universal-mac.zip")")"
+sed -i "s#hash = \".*\"#hash = \"$DARWIN_HASH\"#g" darwin.nix
+
+echo "Updated gdevelop to $LATEST_VER"