build(deps): bump github.com/prometheus/client_golang

Bumps [github.com/prometheus/client_golang](https://github.com/prometheus/client_golang) from 1.5.0 to 1.5.1.
- [Release notes](https://github.com/prometheus/client_golang/releases)
- [Changelog](https://github.com/prometheus/client_golang/blob/master/CHANGELOG.md)
- [Commits](prometheus/client_golang@v1.5.0...v1.5.1)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

go.mod

@@ -8,7 +8,7 @@ require (
 	github.com/dgraph-io/ristretto v0.0.0-20191010170704-2ba187ef9534
 	github.com/go-redis/redis/v7 v7.2.0
 	github.com/golang/mock v1.4.3
-	github.com/prometheus/client_golang v1.5.0
+	github.com/prometheus/client_golang v1.5.1
 	github.com/stretchr/testify v1.5.1
 	github.com/vmihailenco/msgpack v4.0.4+incompatible
 	google.golang.org/appengine v1.6.1 // indirect

go.sum

@@ -81,6 +81,8 @@ github.com/prometheus/client_golang v1.4.1 h1:FFSuS004yOQEtDdTq+TAOLP5xUq63KqAFY
 github.com/prometheus/client_golang v1.4.1/go.mod h1:e9GMxYsXl05ICDXkRhurwBS4Q3OK1iX/F2sw+iXX5zU=
 github.com/prometheus/client_golang v1.5.0 h1:Ctq0iGpCmr3jeP77kbF2UxgvRwzWWz+4Bh9/vJTyg1A=
 github.com/prometheus/client_golang v1.5.0/go.mod h1:e9GMxYsXl05ICDXkRhurwBS4Q3OK1iX/F2sw+iXX5zU=
+github.com/prometheus/client_golang v1.5.1 h1:bdHYieyGlH+6OLEk2YQha8THib30KP0/yD0YH9m6xcA=
+github.com/prometheus/client_golang v1.5.1/go.mod h1:e9GMxYsXl05ICDXkRhurwBS4Q3OK1iX/F2sw+iXX5zU=
 github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910/go.mod h1:MbSGuTsp3dbXC40dX6PRTWyKYBIrTGTE9sqQNg2J8bo=
 github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90 h1:S/YWwWx/RA8rT8tKFRuGUZhuA90OyIBpPCXkcbwU8DE=
 github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=