build(deps): bump github.com/kr/pretty from 0.1.0 to 0.2.1

Bumps [github.com/kr/pretty](https://github.com/kr/pretty) from 0.1.0 to 0.2.1.
- [Release notes](https://github.com/kr/pretty/releases)
- [Commits](kr/pretty@v0.1.0...v0.2.1)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

go.mod

@@ -5,7 +5,7 @@ go 1.12
 require (
 	github.com/golang/protobuf v1.3.1
 	github.com/google/btree v1.0.0
-	github.com/kr/pretty v0.1.0
+	github.com/kr/pretty v0.2.1
 	github.com/mattn/go-runewidth v0.0.4 // indirect
 	github.com/openacid/errors v0.8.1
 	github.com/openacid/low v0.1.7

go.sum

@@ -8,6 +8,8 @@ github.com/google/btree v1.0.0 h1:0udJVsspx3VBr5FwtLhQQtuAsVc79tTq0ocGIPAU6qo=
 github.com/google/btree v1.0.0/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
 github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
+github.com/kr/pretty v0.2.1 h1:Fmg33tUaq4/8ym9TJN1x7sLJnHVwhP33CNkpYV/7rwI=
+github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=