build(deps): bump gopkg.in/DataDog/dd-trace-go.v1 from 1.15.0 to 1.16.0 (#3018)

Bumps [gopkg.in/DataDog/dd-trace-go.v1](https://github.com/DataDog/dd-trace-go) from 1.15.0 to 1.16.0.
- [Release notes](https://github.com/DataDog/dd-trace-go/releases)
- [Commits](https://github.com/DataDog/dd-trace-go/compare/v1.15.0...v1.16.0)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

go.mod

@@ -56,7 +56,7 @@ require (
 	golang.org/x/sys v0.0.0-20190626221950-04f50cda93cb
 	google.golang.org/genproto v0.0.0-20190701230453-710ae3a149df // indirect
 	google.golang.org/grpc v1.22.0
-	gopkg.in/DataDog/dd-trace-go.v1 v1.15.0
+	gopkg.in/DataDog/dd-trace-go.v1 v1.16.0
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	k8s.io/api v0.0.0-20190313235455-40a48860b5ab
 	k8s.io/apimachinery v0.0.0-20190313205120-d7deff9243b1

go.sum

@@ -342,6 +342,8 @@ google.golang.org/grpc v1.22.0 h1:J0UbZOIrCAl+fpTOf8YLs4dJo8L/owV4LYVtAXQoPkw=
 google.golang.org/grpc v1.22.0/go.mod h1:Y5yQAOtifL1yxbo5wqy6BxZv8vAUGQwXBOALyacEbxg=
 gopkg.in/DataDog/dd-trace-go.v1 v1.15.0 h1:2LhklnAJsRSelbnBrrE5QuRleRDkmOh2JWxOtIX6yec=
 gopkg.in/DataDog/dd-trace-go.v1 v1.15.0/go.mod h1:DVp8HmDh8PuTu2Z0fVVlBsyWaC++fzwVCaGWylTe3tg=
+gopkg.in/DataDog/dd-trace-go.v1 v1.16.0 h1:M+pIoj6uFByW3E8KaAaBmsLl3Sma3JzXZ9eo7ffyX5A=
+gopkg.in/DataDog/dd-trace-go.v1 v1.16.0/go.mod h1:DVp8HmDh8PuTu2Z0fVVlBsyWaC++fzwVCaGWylTe3tg=
 gopkg.in/alecthomas/kingpin.v2 v2.2.6/go.mod h1:FMv+mEhP44yOT+4EoQTLFTRgOQ1FBLkstjWtayDeSgw=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=