Use build to create distributions

[xrmx]

What does this pull request do?

Instead of calling setup.py. This fixes the name of built distributions to match pep625, i.e. elastic_apm instead of elastic-apm.

Related issues

Closes #2159

[v1v]

How will this change look like in https://test.pypi.org/project/elastic-apm/ and https://pypi.org/project/elastic-apm/?

[xrmx]

How will this change look like in https://test.pypi.org/project/elastic-apm/ and https://pypi.org/project/elastic-apm/?

It will build wheels and tarballs named elastic_apm instead of elastic-apm:

-rw-rw-r-- 1 rm rm 169731 mag 31 10:09 elastic-apm-6.22.2.tar.gz
-rw-rw-r-- 1 rm rm 351466 nov 25 12:06 elastic_apm-6.23.0-py2.py3-none-any.whl
-rw-rw-r-- 1 rm rm 169730 nov 25 12:06 elastic_apm-6.23.0.tar.gz

The package name is not changed. elastic-opentelemetry is already using build and uploading elastic_opentelemetry-* files.