version bump to 2.5.12 + changelog

CHANGELOG.md

 # Changelog
 
+### Version 2.5.12
+* Jingle file transfer fixes
+
 ### Version 2.5.11
 * Fixed crash on Android <5.0
 

build.gradle

@@ -84,8 +84,8 @@ android {
     defaultConfig {
         minSdkVersion 16
         targetSdkVersion 28
-        versionCode 341
-        versionName "2.5.11"
+        versionCode 343
+        versionName "2.5.12"
         archivesBaseName += "-$versionName"
         applicationId "eu.siacs.conversations"
         resValue "string", "applicationId", applicationId