Install breaks if cask not installed

[CalumFreeman]

Describe the bug
The readme install instructions fail if cask is not already installed

Steps to Reproduce the behaviour
Running the commands suggested in the install instructions

git clone https://github.com/vedang/pdf-tools
cd pdf-tools
make -s

gives the following error

Using Emacs 29.4
make: cask: No such file or directory
make: *** [Makefile:49: .cask/29.4] Error 127

What is the expected behaviour?
pdf-tools should install

Desktop

• OS: Manjaro
• Emacs Version: 29.4

Additional context

I think the solution is to install cask

git clone https://github.com/cask/cask
make -C cask install

before installing pdf-tools.

I'd suggest adding a check to the makefile to see if cask is installed, if it isn't then run the lines above which will install it. Or if that isn't trivial then update the readme to say cask needs to be installed.

(I'm still having issues with the wrong poppler version, so I can't confirm installing cask fixed things, but with cask installed make gets further than it would without)