fix for issue #45

CHANGELOG.md

@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 ### Fixed
 - Support for yaml merge keys, by [@bradrydzewski](https://github.com/bradrydzewski).
+- Escape values with colons, by [@bradrydzewski](https://github.com/bradrydzewski). Issue [#45](https://github.com/drone/drone-yaml/issues/45).
 
 ## [1.0.9] - 2019-05-20
 ### Added

yaml/pretty/util.go

@@ -65,7 +65,7 @@ func isZero(v interface{}) bool {
 
 func isQuoted(b rune) bool {
 	switch b {
-	case '#', ',', '[', ']', '{', '}', '&', '*', '!', '|', '>', '\'', '"', '%', '@', '`':
+	case ':', '#', ',', '[', ']', '{', '}', '&', '*', '!', '|', '>', '\'', '"', '%', '@', '`':
 		return true
 	case '\a', '\b', '\f', '\n', '\r', '\t', '\v':
 		return true