Update brews to use sha256

[convenient]

Error: Calling Formula.sha1 is disabled!
Use Formula.sha256 instead.

The following changes should allow this module to install again, previously sha1 was merely deprecated and produced a warning but with this amendment we should be able to bypass the error.

Methodology:

1. wget the path in the url
2. shasum -a1 zlib-1.2.8.tar.gz and compare the output with the sha currently defined so that they match, and that we can confirm the new sha is valid.
3. shasum -a256 zlib-1.2.8.tar.gz
4. update the file to use 256 with the newly defined sha

Note the TODO in freetype, I am not sure what this piece of code is doing, it doesn't trigger on my el capitan machine. Simply changing this to sha256 stops my code outright dying, but doesn't seem to trigger anything. Any pointers?

[jacobbednarz]

For freetype, you might want to check out the upstream version. It has a slightly different configuration which might explain why it's not doing anything on El Capitan.