scripts/test-infra: add logcheck to verify script

Now that we've migrated to structured logging add a verification step to
verify that future additions/changes to logging comply.

scripts/test-infra/logcheck.conf

@@ -0,0 +1 @@
+-structured sigs.k8s.io/node-feature-discovery/pkg/utils/grpc_log.go

scripts/test-infra/verify.sh

@@ -1,5 +1,7 @@
 #!/bin/bash -e
 
+this_dir=`dirname $0`
+
 # Install deps
 gobinpath="$(go env GOPATH)/bin"
 curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh| sh -s -- -b "$gobinpath" v1.52.2
@@ -15,6 +17,8 @@ curl https://keybase.io/codecovsecurity/pgp_keys.asc | gpg --no-default-keyring
 curl -Os https://uploader.codecov.io/latest/linux/codecov
 chmod +x codecov
 
+go install sigs.k8s.io/logtools/logcheck@v0.5.0
+
 # Run verify steps
 echo "Checking gofmt"
 make gofmt-verify
@@ -25,6 +29,9 @@ make ci-lint
 echo "Running Helm lint"
 make helm-lint
 
+echo "Running logcheck"
+logcheck -config "${this_dir}/logcheck.conf" ./cmd/... ./pkg/...  ./source/...
+
 echo "Running unit tests"
 make test