net/speedtest-go: update to 1.8.2

Changes: https://github.com/showwin/speedtest-go/compare/v1.7.11...v1.8.0
Changes: https://github.com/showwin/speedtest-go/compare/v1.8.0...v1.8.1
Changes: https://github.com/showwin/speedtest-go/compare/v1.8.1...v1.8.2