Update version in ISSUES_TEMPLATE

Author: Ranjan Dasgupta

.github/ISSUE_TEMPLATE.md

@@ -1,8 +1,8 @@
 Please fill out the form below before submitting, thank you!
 
-- [ ] Bug exists Release Version 1.2.3 ( Master Branch)
-- [ ] Bug exists in MQTTv3 Client on Snapshot Version 1.2.4-SNAPSHOT (Develop Branch)
-- [ ] Bug exists in MQTTv5 Client on Snapshot Version 1.2.3-SNAPSHOT (Develop Branch)
+- [ ] Bug exists Release Version 1.2.5 ( Master Branch)
+- [ ] Bug exists in MQTTv3 Client on Snapshot Version 1.2.6-SNAPSHOT (Develop Branch)
+- [ ] Bug exists in MQTTv5 Client on Snapshot Version 1.2.6-SNAPSHOT (Develop Branch)
 
 
 If this is a bug regarding the Android Service, please raise the bug here instead: https://github.com/eclipse/paho.mqtt.android/issues/new