No, Goto is still on the todo list.
We know that this is a very asked feature, but it needs a lot of work.
This may sound strange, but there is no way of representing your example in a programming language (Java/C/PHP/C##/C++...) without repeating "activity1".
You will have to write something like:
if (condition1()) {
if (condition2()) {
activity2();
} else {
activity1();
}
} else {
activity1();
}
This impossibility to write your algorithm without repeating activity1() is the key of the issue here.
Somehow, you have to break execution flow, and this is not (yet) possible with PlantUML.