Remove enable-beta-ecosystems.

It is [no longer required for enabling Bazel support](dependabot/dependabot-core#2196 (comment)).

RELNOTES=n/a
FUTURE_COPYBARA_INTEGRATE_REVIEW=#238 from google:dependabot/bazel/dependencies-f5dc604b06 f1c4797
PiperOrigin-RevId: 836302621

Author: cpovirk

.github/dependabot.yml

@@ -1,5 +1,4 @@
 version: 2
-enable-beta-ecosystems: true # for Bazel support
 updates:
   - package-ecosystem: "bazel"
     directory: "/"

MODULE.bazel

@@ -15,7 +15,7 @@
 module(name = "google_bazel_common")
 
 bazel_dep(name = "bazel_skylib", version = "1.8.2")
-bazel_dep(name = "rules_java", version = "9.0.0")
+bazel_dep(name = "rules_java", version = "9.0.3")
 bazel_dep(name = "rules_jvm_external", version = "6.9")
 bazel_dep(name = "rules_shell", version = "0.6.1")