[grafana二次开发]解决 golang.org/x 无法下载的的问题

原理：

找到go.mod文件，替换掉被墙的地址。

文件末尾加入：

replace (
    cloud.google.com/go => github.com/googleapis/google-cloud-go v0.46.3
    cloud.google.com/go/bigquery => github.com/googleapis/google-cloud-go/bigquery v1.0.0
    cloud.google.com/go/datastore => github.com/googleapis/google-cloud-go/datastore v1.0.0
    cloud.google.com/go/pubsub => github.com/googleapis/google-cloud-go/pubsub v1.0.0
    golang.org/x/crypto => github.com/golang/crypto v0.0.0-20190927123631-a832865fa7ad
    golang.org/x/exp => github.com/golang/exp v0.0.0-20190927203820-447a159532ef
    golang.org/x/image => github.com/golang/image v0.0.0-20190910094157-69e4b8554b2a
    golang.org/x/lint => github.com/golang/lint v0.0.0-20190909230951-414d861bb4ac
    golang.org/x/mobile => github.com/golang/mobile v0.0.0-20190923204409-d3ece3b6da5f
    golang.org/x/mod => github.com/golang/mod v0.1.0
    golang.org/x/net => github.com/golang/net v0.0.0-20190926025831-c00fd9afed17
    golang.org/x/oauth2 => github.com/golang/oauth2 v0.0.0-20190604053449-0f29369cfe45
    golang.org/x/sync => github.com/golang/sync v0.0.0-20190911185100-cd5d95a43a6e
    golang.org/x/sys => github.com/golang/sys v0.0.0-20190927073244-c990c680b611
    golang.org/x/text => github.com/golang/text v0.3.2
    golang.org/x/time => github.com/golang/time v0.0.0-20190921001708-c4c64cad1fd0
    golang.org/x/tools => github.com/golang/tools v0.0.0-20190929041059-e7abfedfabcf
    golang.org/x/xerrors => github.com/golang/xerrors v0.0.0-20190717185122-a985d3407aa7
    google.golang.org/api => github.com/googleapis/google-api-go-client v0.10.0
    google.golang.org/appengine => github.com/golang/appengine v1.6.4
    google.golang.org/genproto => github.com/googleapis/go-genproto v0.0.0-20190927181202-20e1ac93f88c
    google.golang.org/grpc => github.com/grpc/grpc-go v1.24.0

)