Bumped the max number of jobs to 128. (#2120)

Over at `rules_rust` we are organically (not due to matrix abuse)
hitting the 80 job limit and would benefit from having the ability to
run more jobs to support bzlmod refactors we're looking to do.

Author: UebelAndre

buildkite/bazelci.py

@@ -473,7 +473,7 @@
 
 # The maximum number of tasks allowed in one pipeline yaml config file.
 # This is to prevent accidentally creating too many tasks with the martix testing feature.
-MAX_TASK_NUMBER = 80
+MAX_TASK_NUMBER = 128
 
 _TEST_BEP_FILE = "test_bep.json"
 _SHARD_RE = re.compile(r"(.+) \(shard (\d+)\)")
@@ -946,7 +946,8 @@ def load_config(http_url, file_config, allow_imports=True, bazel_version=None):
 
     if len(config["tasks"]) > MAX_TASK_NUMBER:
         raise BuildkiteException(
-            "The number of tasks in one config file is limited to %s!" % MAX_TASK_NUMBER
+            "The number of tasks in one config file is limited to %s, found %s!"
+            % (MAX_TASK_NUMBER, len(config["tasks"])),
         )
 
     return config