update_gtags.sh lost execution permission

[skywind3000]

Describe the bug

I've been using it for years, but recently I found gtags generation failed in linux box.

after some investigation, the I found the root cause:

the file plat/unix/update_gtags.sh hasn't got a execution permission.

Steps to reproduce

git clone https://github.com/ludovicchabant/vim-gutentags.git
cd gutentags
ls -la plat/unix

and you will found the permission problems.

related issues:

• ERROR: Invalid value for argument cmd and update_gtags.sh is not executable #322
• use gtags failed #332