ferdium: fix and simplify update script

pkgs/applications/networking/instant-messengers/ferdium/update.sh

@@ -1,40 +1,12 @@
 #!/usr/bin/env nix-shell
-#!nix-shell -i bash -p curl gnused nix-prefetch jq
+#!nix-shell -i bash -p git bash curl jq nix-update
 
-set -e
+set -xe
 
 dirname="$(dirname "$0")"
 
-updateHash()
-{
-    version=$1
-    arch=$2
-
-    hashKey="${arch}-linux_hash"
-
-    url="https://github.com/ferdium/ferdium-app/releases/download/v$version/Ferdium-linux-$version-$arch.deb"
-    hash=$(nix-prefetch-url --type sha256 $url)
-    sriHash="$(nix hash to-sri --type sha256 $hash)"
-
-    sed -i "s|$hashKey = \"[a-zA-Z0-9\/+-=]*\";|$hashKey = \"$sriHash\";|g" "$dirname/default.nix"
-}
-
-updateVersion()
-{
-    sed -i "s/version = \"[0-9.]*\";/version = \"$1\";/g" "$dirname/default.nix"
-}
-
-currentVersion=$(cd $dirname && nix eval --raw -f ../../../../.. ferdium.version)
-
 latestTag=$(curl https://api.github.com/repos/ferdium/ferdium-app/releases/latest | jq -r ".tag_name")
 latestVersion="$(expr $latestTag : 'v\(.*\)')"
 
-if [[ "$currentVersion" == "$latestVersion" ]]; then
-    echo "Ferdium is up-to-date: ${currentVersion}"
-    exit 0
-fi
-
-updateVersion $latestVersion
-
-updateHash $latestVersion amd64
-updateHash $latestVersion arm64
+nix-update --version "$latestVersion" --system aarch64-linux --override-filename "$dirname/default.nix" ferdium
+nix-update --version skip --system x86_64-linux --override-filename "$dirname/default.nix" ferdium