Update changelog for 1.2.6

1ee20174 · Sergey Mashkov · GitHub · 87b8c7b7 · 1ee20174
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -28,6 +28,12 @@
 * Fixed server's conditional headers processing
 * Reduced required JDK version for `DefaultHeaders` server feature

+# 1.2.6
+> 25 Nov 2019
+
+* Kotlin 1.3.60
+* Restricted CIO HTTP headers parser
+* Introduced header name and value validation

 # 1.2.5
 > 27 Sep 2019