Lock sass dependency to >=1.64.2 to alleviate deprecation

[irby]

Addresses #447

The current Sass dependency resolution (1.80.6) is raising deprecation warnings around myriad things, which indicates some future Sass updates may introduce breaking changes. The issues lie in the implementation within bootstrap, and there have been numerous issues around the deprecation warnings.

The fact of the matter is, if we want to stay up-to-date on Sass, bootstrap will need to make some changes to address all the deprecation warnings. I did try to update bootstrap, sass, and other auxiliary dependencies to the latest versions, but on top of having to make some changes to our sass files (looking at you, app.scss), it ended up causing styling changes to the website.

As a semi-temporary measure, I suggest we lock the sass dependency down to a version that doesn't have any deprecation warnings, 1.64.2. We may come back to upgrading our other dependencies when the time comes, but don't want to run into the risk of upgrading sass to a version that ends up breaking because of incompatibility with bootstrap code (and sass has made some mentions in their deprecation notices that they may remove support in future releases).

[allella]

@zach2825 @bogdankharchenko any thoughts on locking Sass to silence the deprecation warnings we're getting when it's complied?

The warnings aren't breaking anything, so we could continue to ignore them and expect we'll not have to worry about these when we update the frontend.

Dependabot keeps trying to bump sass, in conflict with this PR to lock it, so that's part of the annoyance with it now
https://github.com/hackgvl/hackgreenville-com/pulls?q=is%3Apr+sass

[irby]

I'd probably be in favor of just bumping sass in accordance to dependabot. It does seem a little silly to bump down sass to a specific version just to avoid warnings. I hope that in due time bootstrap will catch up to no longer have issues with sass stylings.