Update github.com/jaegertracing/jaeger to v1.20.0 (#38)

Fixes #37

Jaeger before version 1.18.1 has known vulnerability.

go.mod

@@ -4,16 +4,17 @@ go 1.13
 
 require (
 	github.com/client9/misspell v0.3.4
-	github.com/gogo/googleapis v1.4.0 // indirect
 	github.com/gogo/protobuf v1.3.1
 	github.com/golang/protobuf v1.4.2
 	github.com/golangci/golangci-lint v1.31.0
 	github.com/google/addlicense v0.0.0-20200906110928-a0294312aa76
-	github.com/jaegertracing/jaeger v1.15.1
+	github.com/jaegertracing/jaeger v1.20.0
 	github.com/opentracing/opentracing-go v1.2.0 // indirect
 	github.com/ory/go-acc v0.2.6
 	github.com/pavius/impi v0.0.3
 	github.com/stretchr/testify v1.6.1
 	go.opencensus.io v0.22.4
+	golang.org/x/tools v0.0.0-20201007032633-0806396f153e // indirect
+	google.golang.org/protobuf v1.25.0 // indirect
 	honnef.co/go/tools v0.0.1-2020.1.5
 )