WIP: Start preparing release v3.0.7 (#147)

* Use ooni/probe-engine 0.16.0
* Update all the other dependencies
* Use GitHub Actions rather than Travis CI
* Automatically build and test binaries on the target OS (for Windows, macOS, Linux on amd64)
* Make sure we correctly measure coverage
* Make sure we use `-race` when running tests
* Remove unnecessary scripts
* Make sure the README is up-to-date
* Write small script to update binary data and add GitHub Actions checks for it
* Notice that we needed to run ./updatebindata.sh and run it
* Self documenting instructions regarding cross compiling
* Set version number to v3.0.7-beta

Part of https://github.com/ooni/probe-engine/issues/748

nettests/web_connectivity.go

@@ -50,9 +50,6 @@ func (n WebConnectivity) Run(ctl *Controller) error {
 	if err != nil {
 		return err
 	}
-	if err := builder.SetOptionString("LogLevel", "INFO"); err != nil {
-		return err
-	}
 	return ctl.Run(builder, urls)
 }