Improve Advanced Usage examples (#645)

* docs: fix outputs python-version example and description

Description was lacking words, example was misleading (id was set to cp310 which clearly was a reference to CPython 3.10, but the id is referring to the setup-python action!

* docs: copy-editing in advanced-usage.md

Signed-off-by: Stephen L. <lrq3000@gmail.com>

* docs: add example if statement in advanced-usage.md

Signed-off-by: Stephen L. <lrq3000@gmail.com>

* docs: implement changes suggested by @mahabaleshwars (deprecate pypy2.7, 3.7, 3.8, tweak example, remove wildcard *)

Signed-off-by: Stephen L. <LRQ3000@gmail.com>

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Signed-off-by: Stephen L. <lrq3000@gmail.com>
Signed-off-by: Stephen L. <LRQ3000@gmail.com>