Add a dep to rules_proto

The bb-browser code base depends on it. When this repo is built
directory, Bazel seems a bit sloppy and doesn't require that it's
declared explicitly. This ends up causing failures when another
repository wants to depends on bb-browser.

Fixes: #51

Author: stagnation

MODULE.bazel

@@ -8,6 +8,7 @@ bazel_dep(name = "gazelle", version = "0.35.0")
 bazel_dep(name = "protobuf", version = "23.1")
 bazel_dep(name = "rules_go", version = "0.46.0")
 bazel_dep(name = "rules_jsonnet", version = "0.5.0")
+bazel_dep(name = "rules_proto", version = "6.0.0-rc2")
 bazel_dep(name = "toolchains_llvm", version = "1.0.0")
 
 git_override(