Update Go modules

* Set Go minimum version to 1.13 to support `%w` in errors.
* Bump all modules to the latest versions.

Signed-off-by: SuperQ <superq@gmail.com>

go.mod

@@ -1,22 +1,20 @@
 module github.com/prometheus/common
 
 require (
-	github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d // indirect
 	github.com/go-kit/log v0.1.0
-	github.com/golang/protobuf v1.4.2
-	github.com/jpillora/backoff v1.0.0 // indirect
+	github.com/golang/protobuf v1.4.3
 	github.com/julienschmidt/httprouter v1.3.0
 	github.com/matttproud/golang_protobuf_extensions v1.0.1
 	github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f
 	github.com/pkg/errors v0.9.1
-	github.com/prometheus/client_golang v1.7.1
+	github.com/prometheus/client_golang v1.10.0
 	github.com/prometheus/client_model v0.2.0
-	github.com/sirupsen/logrus v1.6.0
-	golang.org/x/net v0.0.0-20200625001655-4c5254603344
-	golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421
-	golang.org/x/sys v0.0.0-20200625212154-ddb9806d33ae
+	github.com/sirupsen/logrus v1.8.1
+	golang.org/x/net v0.0.0-20210525063256-abc453219eb5
+	golang.org/x/oauth2 v0.0.0-20210514164344-f6687ab2804c
+	golang.org/x/sys v0.0.0-20210603081109-ebe580a85c40
 	gopkg.in/alecthomas/kingpin.v2 v2.2.6
-	gopkg.in/yaml.v2 v2.3.0
+	gopkg.in/yaml.v2 v2.4.0
 )
 
-go 1.11
+go 1.13