Remove explicit mention of bazel 4.x support (#1146)

README.md

@@ -13,11 +13,7 @@ Documentation for all rules and providers are available at: https://bazelbuild.g
 
 ## Bazel versions compatibility
 
-Works with Bazel after 4.2.0.
-
-The following flags are required in Bazel 4.x but not Bazel 5.x or newer:
-
-- `--experimental_enable_aggregating_middleman=False`
+Works with Bazel after 5.4.0.
 
 Note that the rules may be compatible with older versions of Bazel but support may break
 in future changes as these older versions are not tested.

examples/WORKSPACE.bazel

@@ -85,14 +85,6 @@ rbe_preconfig(
     toolchain = "ubuntu1804-bazel-java11",
 )
 
-# TODO: Remove once bazel 4.x is no longer supported
-http_archive(
-    name = "rules_proto",
-    sha256 = "20b240eba17a36be4b0b22635aca63053913d5c1ee36e16be36499d167a2f533",
-    strip_prefix = "rules_proto-11bf7c25e666dd7ddacbcd4d4c4a9de7a25175f8",
-    urls = ["https://github.com/bazelbuild/rules_proto/archive/11bf7c25e666dd7ddacbcd4d4c4a9de7a25175f8.tar.gz"],
-)
-
 http_archive(
     name = "build_bazel_apple_support",
     patches = ["//deps:apple_support.patch"],