---➤ go get -u github.com/prometheus-community/pro-bing
go: downloading github.com/prometheus-community/pro-bing v0.1.0
go: github.com/prometheus-community/pro-bing@v0.1.0: verifying module: github.com/prometheus-community/pro-bing@v0.1.0: checking tree#15554181 against tree#15705495: reading https://goproxy.io/sumdb/sum.golang.org/tile/8/1/237: 404 Not Found
server response: not found