Bump protobuf dependency to fix build with Bazel < 8

.bcr/presubmit.yml

diff --git a/.bcr/presubmit.yml b/.bcr/presubmit.yml
index f7bceee..1db4f45 100644
--- a/.bcr/presubmit.yml
+++ b/.bcr/presubmit.yml
@@ -1,6 +1,6 @@
 matrix:
   platform: ["centos7", "debian10", "macos", "ubuntu2004", "windows"]
-  bazel: ['7.x', '6.x']
+  bazel: ['7.x', '8.x']
 tasks:
   verify_build_targets:
     name: "Verify build targets"

MODULE.bazel

diff --git a/MODULE.bazel b/MODULE.bazel
index 2a69659..2799d52 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -7,7 +7,7 @@
     compatibility_level = 1,
 )
 
-bazel_dep(name = "protobuf", version = "27.1", repo_name = "com_google_protobuf")
+bazel_dep(name = "protobuf", version = "29.0", repo_name = "com_google_protobuf")
 bazel_dep(name = "bazel_skylib", version = "1.3.0")
 bazel_dep(name = "rules_cc", version = "0.0.15")
 bazel_dep(name = "rules_license", version = "0.0.7")

MODULE.bazel.lock

diff --git a/MODULE.bazel.lock b/MODULE.bazel.lock
index df66d56..87034ca 100644
--- a/MODULE.bazel.lock
+++ b/MODULE.bazel.lock
@@ -50,7 +50,6 @@
     "https://bcr.bazel.build/modules/platforms/0.0.8/MODULE.bazel": "9f142c03e348f6d263719f5074b21ef3adf0b139ee4c5133e2aa35664da9eb2d",
     "https://bcr.bazel.build/modules/protobuf/21.7/MODULE.bazel": "a5a29bb89544f9b97edce05642fac225a808b5b7be74038ea3640fae2f8e66a7",
     "https://bcr.bazel.build/modules/protobuf/27.0/MODULE.bazel": "7873b60be88844a0a1d8f80b9d5d20cfbd8495a689b8763e76c6372998d3f64c",
-    "https://bcr.bazel.build/modules/protobuf/27.1/MODULE.bazel": "703a7b614728bb06647f965264967a8ef1c39e09e8f167b3ca0bb1fd80449c0d",
     "https://bcr.bazel.build/modules/protobuf/29.0-rc2/MODULE.bazel": "6241d35983510143049943fc0d57937937122baf1b287862f9dc8590fc4c37df",
     "https://bcr.bazel.build/modules/protobuf/29.0/MODULE.bazel": "319dc8bf4c679ff87e71b1ccfb5a6e90a6dbc4693501d471f48662ac46d04e4e",
     "https://bcr.bazel.build/modules/protobuf/29.0/source.json": "b857f93c796750eef95f0d61ee378f3420d00ee1dd38627b27193aa482f4f981",