Update requirements.txt

[himalalps]

According to https://github.com/SHMinger/ScienceDecrypting, the version of pypdf2 should be 1.26.0. Otherwise, there might be version error.

[yundebian918]

请问能否帮忙下载《李约瑟中国科学技术史第五卷化学及相关技术第十二分册陶瓷技术》这本书？谢谢！

[SlC145]

Traceback (most recent call last):
File "D:\Desktop\ScienceDecrypting-master\ScienceDecrypting-master\decrypt.py", line 387, in
main()
File "D:\Desktop\ScienceDecrypting-master\ScienceDecrypting-master\decrypt.py", line 382, in main
decrypt_file(options.src, options.dst)
File "D:\Desktop\ScienceDecrypting-master\ScienceDecrypting-master\decrypt.py", line 319, in decrypt_file
raise CustomException("文件格式错误 {}".format(tail))
CustomException: 文件格式错误 b'\nstartxref\r\n181284201\r\n%%EOF\r\n'
这是为啥