Add a TODO referencing b/519583193

PiperOrigin-RevId: 926798037
Change-Id: If3cd8bdc1f03f582df213a8390240b0accaf5658

rules/dex.bzl

diff --git a/rules/dex.bzl b/rules/dex.bzl
index b83226c..96ea2a8 100644
--- a/rules/dex.bzl
+++ b/rules/dex.bzl
@@ -355,6 +355,7 @@
         inputs = inputs,
         arguments = [args],
         mnemonic = "ShardForMultidex",
+        # TODO(b/519583193): update CPU reservation when b/519583193 is implemented
         execution_requirements = {"cpu:4": ""},  # see b/501344408
         progress_message = "Assembling dex files for " + ctx.label.name,
         use_default_shell_env = True,