go vet fails

[kixelated]

Broken by #527

# github.com/pions/webrtc/examples/data-channels
examples/data-channels/main.go:38:3: Printf format %s arg d.Label is a func value, not called
examples/data-channels/main.go:42:4: Printf format %s arg d.Label is a func value, not called
examples/data-channels/main.go:58:4: Printf format %s arg d.Label is a func value, not called
# github.com/pions/webrtc/examples/data-channels-close
examples/data-channels-close/main.go:42:3: Printf format %s arg d.Label is a func value, not called
examples/data-channels-close/main.go:46:4: Printf format %s arg d.Label is a func value, not called
examples/data-channels-close/main.go:51:5: Printf format %s arg d.Label is a func value, not called
examples/data-channels-close/main.go:68:6: Printf format %s arg d.Label is a func value, not called
examples/data-channels-close/main.go:80:4: Printf format %s arg d.Label is a func value, not called
# github.com/pions/webrtc/examples/data-channels-create
examples/data-channels-create/main.go:44:3: Printf format %s arg dataChannel.Label is a func value, not called
examples/data-channels-create/main.go:60:3: Printf format %s arg dataChannel.Label is a func value, not called
# github.com/pions/webrtc/examples/data-channels-detach
examples/data-channels-detach/main.go:52:3: Printf format %s arg d.Label is a func value, not called
examples/data-channels-detach/main.go:56:4: Printf format %s arg d.Label is a func value, not called
# github.com/pions/webrtc/examples/data-channels-detach-create
examples/data-channels-detach-create/main.go:58:3: Printf format %s arg dataChannel.Label is a func value, not called
# github.com/pions/webrtc/examples/ortc
examples/ortc/main.go:49:3: Printf format %s arg channel.Label is a func value, not called
examples/ortc/main.go:54:4: Printf format %s arg channel.Label is a func value, not called
examples/ortc/main.go:134:4: Printf format %s arg channel.Label is a func value, not called
examples/ortc/main.go:153:3: Printf format %s arg channel.Label is a func value, not called
# github.com/pions/webrtc/examples/pion-to-pion/answer
examples/pion-to-pion/answer/main.go:44:3: Printf format %s arg d.Label is a func value, not called
examples/pion-to-pion/answer/main.go:48:4: Printf format %s arg d.Label is a func value, not called
examples/pion-to-pion/answer/main.go:64:4: Printf format %s arg d.Label is a func value, not called
# github.com/pions/webrtc/examples/pion-to-pion/offer
examples/pion-to-pion/offer/main.go:51:3: Printf format %s arg dataChannel.Label is a func value, not called
examples/pion-to-pion/offer/main.go:67:3: Printf format %s arg dataChannel.Label is a func value, not called

[Sean-Der]

Blocked by golangci/golangci-lint#416 :(

I will fix this and update CI to run golangci-lint twice.