servo: add update script

pkgs/by-name/se/servo/package.nix

···
       --prefix LD_LIBRARY_PATH : ${runtimePaths}
   '';
 
+  passthru.updateScript = ./update.sh;
+
   meta = {
     description = "The embeddable, independent, memory-safe, modular, parallel web rendering engine";
     homepage = "https://servo.org";

pkgs/by-name/se/servo/update.sh

···
+#!/usr/bin/env nix-shell
+#!nix-shell -i bash -p coreutils common-updater-scripts curl jq nix-update
+
+# This update script exists, because nix-update is unable to ignore various
+# bogus tags that exist on the upstream repo e.g.
+#  - selectors-v0.18.0/v0.20.0/v0.21.0/v0.22.0
+#  - homu-tmp
+#
+# Once https://github.com/Mic92/nix-update/issues/322 is resolved it can be
+# removed.
+
+set -exuo pipefail
+
+# Determine latest commit id and date
+TMP=$(mktemp)
+curl -o "$TMP" https://api.github.com/repos/servo/servo/commits/main
+COMMIT_ID=$(jq -r '.sha' "$TMP")
+COMMIT_TIMESTAMP=$(jq -r '.commit.author.date' "$TMP")
+COMMIT_DATE=$(date -d "$COMMIT_TIMESTAMP" +"%Y-%m-%d")
+rm $TMP
+
+cd "$(git rev-parse --show-toplevel)"
+
+# Update version, src
+update-source-version servo "0-unstable-${COMMIT_DATE}" --file=pkgs/by-name/se/servo/package.nix --rev="$COMMIT_ID"
+
+# Update cargoHash
+nix-update --version=skip servo