SVG mime type is incorrect

[harmin-parra]

Describe the bug
The SVG mime type used by Allure is incorrect

The Allure current mime type: image/svg-xml

allure-python/allure-python-commons/src/types.py

Line 56 in 20ba28a

SVG = ("image/svg-xml", "svg")

The correct mime type is image/svg+xml

Reference:
https://www.w3.org/TR/SVG11/intro.html#:~:text=The%20MIME%20type%20for%20SVG,XML%20Media%20Types%20%5BRFC3023%5D).