add changelog for 3.6.1 and 3.6.2

Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

CHANGELOG.md

@@ -1,3 +1,24 @@
+## 3.6.2 (May, 23, 2019)
+
+- fix bug when creating preview
+- fix crash on opening app
+- fix account switch
+- fix jumping to top on sync
+
+For a full list, please see https://github.com/nextcloud/android/milestone/34
+
+## 3.6.1 (May, 12, 2019)
+
+- show reshares correctly
+- allow open files from Talk
+- collabora: hide loading delay warning if document is loaded
+- correctly show idn string in drawer
+- show outdated warning on NC13
+- enhance pass protection system
+- bugfixes
+
+For a full list, please see https://github.com/nextcloud/android/milestone/33
+
 ## 3.6.0 (April, 09, 2019)
 
 - remove "expert mode"