update version to 0.6.0 (#572)

Signed-off-by: xiaolongran <xiaolongran@tencent.com>

update version to 0.6.0
diff --git a/VERSION b/VERSION
index 8d1f998..cf25392 100644
--- a/VERSION
+++ b/VERSION
@@ -1,3 +1,3 @@
 // This version number refers to the currently released version number
 // Please fix the version when release.
-v0.5.0
+v0.6.0
diff --git a/stable.txt b/stable.txt
index 3270adc..71c317e 100644
--- a/stable.txt
+++ b/stable.txt
@@ -1,3 +1,3 @@
 // This version number refers to the current stable version, generally is `VERSION - 1`.
 // Please fix the version when release.
-v0.5.0
+v0.6.0