Update favicons dependency to v5.3.0

[Turbo87]

... and also change it back to ^ constraint to take advantage of bugfixes and new features

[Turbo87]

@davewasmer @Exelord any thoughts on this? this PR will be needed to actually be able to use the appShortName option

[Exelord]

I'm not a fan of ^ in dependencies as we talk earlier. The packages can introduce bugs without any notice with every version and we will populate that to every production apps. It's like setting a project with ember version of ^3.0. Theoritcaly everything should be backword compatible but we know that bugs happen sometimes.

Are you sure we want to follow this pattern here?

[Turbo87]

the issues you're describing are solved by using lockfiles, that lock all dependencies to specific versions, instead of just the top-level deps.

Are you sure we want to follow this pattern here?

I am pretty sure about it, since I use it in literally all other projects too. I can change it in this PR if you don't agree, but I really see no point in pinning it to specific versions unless there actually is a known compat issue with an upstream dependency.

One example was QUnit, which dropped support for Node 4 without increasing their major version. Arguably they should have done that to comply with semver, but they didn't. ember-qunit always used a ^ constraint on the qunit dependency, but as soon as we were aware of their change we pinned the version to the latest compatible version, removed the ^ and then the problem was solved.