[FR] Update release note of 1.5.4

[DimRochette]

I think the release notes are missing a big change in 1.5.4
It is that it's now building with gcc-11 with pull request #1060

I personally found the cause and the fix on gentoo.org I guess it will be easier for many to have this here

[dmah42]

done. thank you for pointing that out!