Bump gopkg.in/yaml.v2 from 2.2.3 to 2.2.4 (#309)

Bumps [gopkg.in/yaml.v2](https://github.com/go-yaml/yaml) from 2.2.3 to 2.2.4.
- [Release notes](https://github.com/go-yaml/yaml/releases)
- [Commits](go-yaml/yaml@v2.2.3...v2.2.4)

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

go.mod

@@ -5,5 +5,5 @@ go 1.12
 require (
 	github.com/BurntSushi/toml v0.3.1
 	github.com/davecgh/go-spew v1.1.1
-	gopkg.in/yaml.v2 v2.2.3
+	gopkg.in/yaml.v2 v2.2.4
 )

go.sum

@@ -7,3 +7,5 @@ gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.3 h1:fvjTMHxHEw/mxHbtzPi3JCcKXQRAnQTBRo6YCJSVHKI=
 gopkg.in/yaml.v2 v2.2.3/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.4 h1:/eiJrUcujPVeJ3xlSWaiNi3uSVmDGBK1pDHUHAnao1I=
+gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=