fix: change JSON patch implementation for memory improvement

[dkundel]

I've done some digging into #985 and here's the outcome.

Actual Issue:
The issue seems to be in the algorithm that the rfc6902 library is using for Arrays. Since it's recursive it will run out of memory when it encounters an array that is too big.

Possible Solution:
I found in this issue chbrown/rfc6902#39 an alternative library (fast-json-patch) that could be used. It seems to work against my use case and according to these benchmarks it should be significantly more performant.

Breaking Change:
As you can see in the updated tests, there are two changes to the output format compared to the other implementation:

1. Order of operations is different
2. path for insertions in arrays ends with new index of item instead of -. For example: /pixels/99 instead of /pixels/-. I checked the actual standard and this behavior seems to be up to the actual standard: https://tools.ietf.org/html/rfc6902#appendix-A.2

Let me know what you think.

[orta]

I think this is a great call.

I'll call it a major semver bump (we've had them for trivial things before) - I think it'd be unlikely people are expecting the order to be determinate but at least this warns folks upfront