build(deps): bump github.com/prometheus/client_model from 0.1.0 to 0.2.0 (#3607)

Bumps [github.com/prometheus/client_model](https://github.com/prometheus/client_model) from 0.1.0 to 0.2.0.
- [Release notes](https://github.com/prometheus/client_model/releases)
- [Commits](https://github.com/prometheus/client_model/compare/v0.1.0...v0.2.0)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

go.mod

@@ -30,7 +30,7 @@ require (
 	github.com/openzipkin-contrib/zipkin-go-opentracing v0.3.5
 	github.com/philhofer/fwd v1.0.0 // indirect
 	github.com/prometheus/client_golang v1.3.0
-	github.com/prometheus/client_model v0.1.0
+	github.com/prometheus/client_model v0.2.0
 	github.com/prometheus/common v0.7.0
 	github.com/tinylib/msgp v1.1.0 // indirect
 	github.com/tmc/grpc-websocket-proxy v0.0.0-20190109142713-0ad062ec5ee5 // indirect

go.sum

@@ -353,6 +353,8 @@ github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90/go.mod h1:
 github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
 github.com/prometheus/client_model v0.1.0 h1:ElTg5tNp4DqfV7UQjDqv2+RJlNzsDtvNAWccbItceIE=
 github.com/prometheus/client_model v0.1.0/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
+github.com/prometheus/client_model v0.2.0 h1:uq5h0d+GuxiXLJLNABMgp2qUWDPiLvgCzz2dUR+/W/M=
+github.com/prometheus/client_model v0.2.0/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
 github.com/prometheus/common v0.2.0/go.mod h1:TNfzLD0ON7rHzMJeJkieUDPYmFC7Snx/y86RQel1bk4=
 github.com/prometheus/common v0.4.1/go.mod h1:TNfzLD0ON7rHzMJeJkieUDPYmFC7Snx/y86RQel1bk4=
 github.com/prometheus/common v0.6.0/go.mod h1:eBmuwkDJBwy6iBfxCBob6t6dR6ENT/y+J+Zk0j9GMYc=