Add kythe_ubuntu2404. (#2157)

diff --git a/buildkite/bazelci.py b/buildkite/bazelci.py
index f798d86..2fc8a69 100755
--- a/buildkite/bazelci.py
+++ b/buildkite/bazelci.py
@@ -346,6 +346,13 @@
         "docker-image": f"gcr.io/{DOCKER_REGISTRY_PREFIX}/ubuntu2204-kythe",
         "python": "python3",
     },
+    "kythe_ubuntu2404": {
+        "name": "Kythe (Ubuntu 24.04 LTS)",
+        "emoji-name": "Kythe (:ubuntu: Ubuntu 24.04 LTS)",
+        "publish_binary": [],
+        "docker-image": f"gcr.io/{DOCKER_REGISTRY_PREFIX}/ubuntu2404-kythe",
+        "python": "python3",
+    },
     "ubuntu2204_java17": {
         "name": "Ubuntu 22.04 (OpenJDK 17, gcc 11.2.0)",
         "emoji-name": ":ubuntu: Ubuntu 22.04 (OpenJDK 17, gcc 11.2.0)",