[ci/build] fix wheel size check (#12396)

Signed-off-by: youkaichao <youkaichao@gmail.com>

.buildkite/check-wheel-size.py

@@ -2,8 +2,10 @@ import os
 import sys
 import zipfile
 
-# Read the VLLM_MAX_SIZE_MB environment variable, defaulting to 250 MB
-VLLM_MAX_SIZE_MB = int(os.environ.get('VLLM_MAX_SIZE_MB', 250))
+# Read the VLLM_MAX_SIZE_MB environment variable, defaulting to 300 MiB
+# Note that we have 400 MiB quota, please use it wisely.
+# See https://github.com/pypi/support/issues/3792 .
+VLLM_MAX_SIZE_MB = int(os.environ.get('VLLM_MAX_SIZE_MB', 300))
 
 
 def print_top_10_largest_files(zip_file):