Update pixbuf to find glib-2.0.so..
Update pixbuf to find glib-2.0.so..

when installed through conda. If `.so` is missing, only a directory named `glib-2.0` might be found.
```
$ ll ~/anaconda-envs/dev/lib/ | grep glib
drwxrwxr-x  3 base base     4096 Mar 18 09:18 glib-2.0
lrwxrwxrwx  1 base base       23 Apr  4 10:04 libglib-2.0.so -> libglib-2.0.so.0.5800.3
lrwxrwxrwx  1 base base       23 Apr  4 10:04 libglib-2.0.so.0 -> libglib-2.0.so.0.5800.3
-rwxrwxr-x  1 base base  1354816 Apr  4 10:04 libglib-2.0.so.0.5800.3
```
SimonSapin/cairocffi