Soon osquery will require that the version of CMake
is not equal or higher than 3.18.0.
We can ignore such requirement since we are not making packages.
See osquery/osquery#6801
Also remove unused sed replacements. Those settings are now the default
when not using the osquery toolchain.
Coverage tests are currently failing. This is most likely due to
exhausting the container disk space. This commit removes downloaded
files and build artifacts, which are not needed for coverage tests.