gfortran issue in Arch Linux and its solution

rstatix package  installation in Arch Linux is stuck due to gfortran being not found. Steps to resolve the issue are as follows

- Install gfortran using your package manager
- Symlink the package as gfortran
eg:

```
yay -S gfortran9-bin
cd /usr/bin
sudo ln -s x86_64-linux-gnu-gfortran-9 gfortran
```