Suggest cabal --store-dir

[Bodigrim]

dr-cabal/README.md

Lines 102 to 107 in af95d44

	> You may prefer a less invasive approach if you have custom global
	> Cabal configurations:
	>
	> ```shell
	> rm -rf ~/.cabal/store
	> ```

I'd like to suggest an even less intrusive approach, without nuking the whole store:

cabal --store-dir=foobar build

Cabal will create if non-existent and use foobar folder to store built packages.

POSIX users can simplify their lifes even further, creating a fresh temporary folder every time:

cabal --store-dir=$(mktemp -d) build

[chshersh]

That sounds like a great suggestion and a really nice documentation improvement 🙂