Update alumni.csv

Author: taogoddd

data/team/alumni.csv

@@ -11,7 +11,7 @@ Dongchan Shin,Intern 2023-24; HKU BEng → Mila,
 Leo Zeyu Liu,Intern 2023; UW BS/MS → UT Austin PhD,https://leo-liuzy.github.io/
 Peng Shi,Visitor 2023; UWaterloo PhD → Amazon,https://scholar.google.com/citations?user=XTbDLrkAAAAJ
 Toh Jing Hua,Intern 2023; NTU BS,https://github.com/ztjhz
-Siheng Zhao,Intern 2023; NJU BS → USC PhD,https://hilbert-johnson.github.io/
+Siheng Zhao,Intern 2023; NJU BS → USC PhD,https://sihengz02.github.io/
 Fan Zhou,Intern 2023; SJTU BS/MS → SJTU PhD,https://koalazf99.github.io/
 Luoxuan Weng,Visiting ZJU PhD 2023,https://luoxuanweng.site/
 Zhoujun Cheng,Intern 2022-23; SJTU BS/MS → UCSD PhD,https://blankcheng.github.io/