switch to go-kit/log (#1575)

Signed-off-by: yeya24 <yb532204897@gmail.com>

vendor/github.com/go-logfmt/logfmt/CHANGELOG.md

@@ -0,0 +1,41 @@
+# Changelog
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [0.4.0] - 2018-11-21
+
+### Added
+- Go module support by [@ChrisHines]
+- CHANGELOG by [@ChrisHines]
+
+### Changed
+- Drop invalid runes from keys instead of returning ErrInvalidKey by [@ChrisHines]
+- On panic while printing, attempt to print panic value by [@bboreham]
+
+## [0.3.0] - 2016-11-15
+### Added
+- Pool buffers for quoted strings and byte slices by [@nussjustin]
+### Fixed
+- Fuzz fix, quote invalid UTF-8 values by [@judwhite]
+
+## [0.2.0] - 2016-05-08
+### Added
+- Encoder.EncodeKeyvals by [@ChrisHines]
+
+## [0.1.0] - 2016-03-28
+### Added
+- Encoder by [@ChrisHines]
+- Decoder by [@ChrisHines]
+- MarshalKeyvals by [@ChrisHines]
+
+[0.4.0]: https://github.com/go-logfmt/logfmt/compare/v0.3.0...v0.4.0
+[0.3.0]: https://github.com/go-logfmt/logfmt/compare/v0.2.0...v0.3.0
+[0.2.0]: https://github.com/go-logfmt/logfmt/compare/v0.1.0...v0.2.0
+[0.1.0]: https://github.com/go-logfmt/logfmt/commits/v0.1.0
+
+[@ChrisHines]: https://github.com/ChrisHines
+[@bboreham]: https://github.com/bboreham
+[@judwhite]: https://github.com/judwhite
+[@nussjustin]: https://github.com/nussjustin