ci: use CGO for tests to enable race detector
```
go: -race requires cgo; enable cgo by setting CGO_ENABLED=1
```
We're explicitly using CGO on macOS now for FSEvents support and
purposefully NOT using CGO on other platforms since we don't need
it.
The race detector (`-race`) requires it, however, so for the e2e
make task, it should alway be on.
Signed-off-by: Milas Bowman <[email protected]>
Milas Bowman