chore: explicitly provide toolchain label to rb_bundle

This satisfies the strict-repo-deps constraint that comes with bzlmod

examples/gem/MODULE.bazel

@@ -10,6 +10,8 @@ local_path_override(
 ruby = use_extension("@rules_ruby//ruby:extensions.bzl", "ruby")
 
 ruby.toolchain(name = "rules_ruby", version = "3.2.1")
+use_repo(ruby, "rules_ruby_dist")
+
 ruby.bundle(
     name = "bundle",
     srcs = [
@@ -21,6 +23,7 @@ ruby.bundle(
         "BUNDLE_BUILD__FOO": "bar",
     },
     gemfile = "//:Gemfile",
+    toolchain = "@rules_ruby_dist//:BUILD",
 )
 
 use_repo(ruby, "rules_ruby_toolchains", "bundle")

ruby/deps.bzl

@@ -3,5 +3,8 @@
 load("//ruby/private:bundle.bzl", _rb_bundle = "rb_bundle")
 load("//ruby/private:download.bzl", _rb_register_toolchains = "rb_register_toolchains")
 
-rb_bundle = _rb_bundle
+def rb_bundle(toolchain = "@rules_ruby_dist//:BUILD", **kwargs):
+    _rb_bundle(
+        toolchain = toolchain,
+        **kwargs)
 rb_register_toolchains = _rb_register_toolchains

ruby/extensions.bzl

@@ -7,6 +7,7 @@ ruby_bundle = tag_class(attrs = {
     "srcs": attr.label_list(),
     "env": attr.string_dict(),
     "gemfile": attr.label(),
+    "toolchain": attr.label(),
 })
 
 ruby_toolchain = tag_class(attrs = {
@@ -23,6 +24,7 @@ def _ruby_module_extension(module_ctx):
                 srcs = bundle.srcs,
                 env = bundle.env,
                 gemfile = bundle.gemfile,
+                toolchain = bundle.toolchain,
             )
 
         for toolchain in mod.tags.toolchain:

ruby/private/bundle.bzl

@@ -10,7 +10,7 @@ def _rb_bundle_impl(repository_ctx):
     binstubs_path = repository_ctx.path("bin")
     bundle_path = repository_ctx.path(".")
     gemfile_path = repository_ctx.path(repository_ctx.attr.gemfile)
-    toolchain_path = repository_ctx.path(Label("@rules_ruby_dist//:BUILD")).dirname
+    toolchain_path = repository_ctx.path(repository_ctx.attr.toolchain).dirname
 
     if repository_ctx.os.name.startswith("windows"):
         bundle = repository_ctx.path("%s/dist/bin/bundle.cmd" % toolchain_path)
@@ -78,6 +78,9 @@ rb_bundle = repository_rule(
 List of Ruby source files used to build the library.
             """,
         ),
+        "toolchain": attr.label(
+            mandatory = True,
+        ),
         "gemfile": attr.label(
             allow_single_file = ["Gemfile"],
             doc = """