Replace xxh64 with the even faster xxh3 for SVG gradient id creation

[vlakoff]

Dedicated issue for the suggestion I raised in #187 (comment):

Nit: the newer xxh3 would be a better choice than xxh64 — it's even faster while keeping the same 64‑bit width.

If someone wants to take this on, the main code change is simply replacing xxh64 with xxh3 in:

BaconQrCode/src/Renderer/Image/SvgImageBackEnd.php

Line 321 in 3feed0e

$id = sprintf('g%d-%s', ++$this->gradientCount, hash('xxh64', $toBeHashed));

The more tedious part is updating the expected id attribute in these 2 snapshot files:

• SVGRenderingTest__testQrWithGradientGeneratesDifferentIdsForDifferentGradients__1.xml
• SVGRenderingTest__testQrWithGradientGeneratesDifferentIdsForDifferentGradients__2.xml

Also, since this change affects the generated SVG output, it should probably be treated as a breaking change.

[DASPRiD]

Also, since this change affects the generated SVG output, it should probably be treated as a breaking change.

I don't see it as a breaking change, as long as it doesn't change the visual result.

[vlakoff]

I don't see it as a breaking change, as long as it doesn't change the visual result.

Actually, I agree with you. I only mentioned it out of caution.