replace M_PI with std::numbers::pi, bump c++ standart to c++20

[w0lek]

Changes requested from here

verilog-to-routing/vtr-verilog-to-routing#3090

[vaughnbetz]

LGTM -- thanks!

[vaughnbetz]

@AmirhosseinPoolad : just pinging you to double check we've moved over to the ezgl submodule and these commits modify it.

[AlexandreSinger]

LGTM, We really need to add a build CI to this repo just to ensure that any changes we make on this side are safe. I will look into that today. I am pretty sure this will be ok.

[AlexandreSinger]

@AmirhosseinPoolad : just pinging you to double check we've moved over to the ezgl submodule and these commits modify it.

Just adding to this, currently Dependabot is set up to track the master branch of EZGL; but just be aware that Dependabot is set up to update VTR once a month. We can decide to make that more frequent if we would like. There are pros and cons to both. If people want a change sooner, they can update the submodule directly (without dependabot) on VTR with no issue.