Install on macOS doesn't work

Using:

`curl --proto '=https' --tlsv1.2 -sLSf "https://github.com/dmtrKovalenko/blendr/blob/main/install.sh?raw=true" | sh`

results in an executable called `$HOME/.local/bin` **i.e., blendr is not put in bin, but is called bin**

The script needs the single line:

`install_dir="$HOME/.local/bin"`

replaced with the two lines:

`mkdir -p "$HOME/.local/bin"`
`install_dir="$HOME/.local/bin/"` **NOTE the trailing slash**

**Note also that the path to blendr is not added to `$PATH`**

Otherwise, blendr seems to work very well, thank you. :-)

Start by reading install.sh and running the provided curl command in a macOS shell. Verify that $HOME/.local/bin is created, blendr is installed inside it rather than under a filename ending in bin, and the installation path is added to $PATH.

Written by the indexing model from the issue text.