Allow concatenation of string and numbers in scripting

[bochen87]

Currently, only concatenation of strings is allowed. Trying to concatenate a number and a string leads to a runtime error

BehaviorTree.CPP/include/behaviortree_cpp/scripting/operators.hpp

Line 255 in 58326a8

else if (rhs_v.isString() && lhs_v.isString() && op == plus)

It would be nice to also allow concatenation of string and numbers

[facontidavide]

I can see the use case, I will put this on my list of "todo".

[bochen87]

I can see the use case, I will put this on my list of "todo".

I made a PR #771