vendor : update cpp-httplib to 0.38.0 (#20578)

Signed-off-by: Adrien Gallouët <angt@huggingface.co>

Author: angt

scripts/sync_vendor.py

@@ -5,7 +5,7 @@
 import sys
 import subprocess
 
-HTTPLIB_VERSION = "refs/tags/v0.37.2"
+HTTPLIB_VERSION = "refs/tags/v0.38.0"
 
 vendor = {
     "https://github.com/nlohmann/json/releases/latest/download/json.hpp":     "vendor/nlohmann/json.hpp",