Prep for archiving: pin to last working releases

This project will soon be archived on Github as it's there
are no plans to further maintain it. I've pinned J2CL and
jsinterop-base to the last working versions and bumped the
bazel version to 5.4.0.

.bazelversion

@@ -1 +1 @@
-5.1.0
+5.4.0

README.md

@@ -1,5 +1,9 @@
 # J2CL Protobuf  · [![Build Status](https://github.com/google/j2cl-protobuf/actions/workflows/ci.yaml/badge.svg)](https://github.com/google/j2cl-protobuf/actions/workflows/ci.yaml)
 
+> [!IMPORTANT]
+> As of March 2025 this project has been archived and will not be receiving
+> further updates.
+
 This repository contains [J2CL](http://j2cl.io) compatible implementation of
 [Protocol Buffers](https://developers.google.com/protocol-buffers).
 

WORKSPACE

@@ -3,7 +3,7 @@ workspace(name = "com_google_j2cl_protobuf")
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
 # Load J2CL separately
-_J2CL_VERSION = "master"
+_J2CL_VERSION = "7856e8b4cace643a8cc088a40eb21ec82dd3a03f"
 
 http_archive(
     name = "com_google_j2cl",

repository.bzl

@@ -2,7 +2,7 @@
 
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
-_JSINTEROP_BASE_VERSION = "master"
+_JSINTEROP_BASE_VERSION = "419d2746c6242bce5bbb651724c8c8962e25df71"
 
 def load_j2cl_proto_repo_deps():
     http_archive(