Fix vendored nonius in C++20

[DethRaid]

C++17 deprecated std::result_of, C++20 removed it. I've switched nonius's usage of std::result_of to std::invoke_result_t

[DethRaid]

Don't merge this yet there's more C++20 problems

[DethRaid]

The OSX - GCC 5 error is:

Error: Unknown command: cask

From line 700 of https://dev.azure.com/adastley/adastley/_build/results?buildId=155&view=logs&j=9b28514c-6684-5172-2358-5b6ae8f577e3&t=9b69e240-1623-58d4-1dff-19d71f2c6fbd&l=700

Did I cause that?

[DethRaid]

I've made all the changes I want to. As soon as we can get this to pass CI, you can merge it

[DethRaid]

New build error:

+ brew install gcc@5
gcc@5: This formula either does not compile or function as expected on macOS
versions newer than High Sierra due to an upstream incompatibility.

I guess GCC 5 is off the table? I don't want to edit the required checks for this repo, yalls should do that

[RichieSams]

New build error:

+ brew install gcc@5
gcc@5: This formula either does not compile or function as expected on macOS
versions newer than High Sierra due to an upstream incompatibility.

I guess GCC 5 is off the table? I don't want to edit the required checks for this repo, yalls should do that

If I had a nickle for every time brew broke CI....

[RichieSams]

Closing in favor of https://github.com/RichieSams/FiberTaskingLib/issues/142 and https://github.com/RichieSams/FiberTaskingLib/issues/143