Log Message:
net/ruby-xdr: update to 3.0.2

3.0.2 (2020-10-20)

Changed

* Relax lower bound for ActiveSupport dependency to support usage in Rails
  4.2 ((#12)[https://github.com/stellar/ruby-xdr/pull/12])

Fixed

* Fix non-bang arm accessors for XDR::Union
  ((#13)[https://github.com/stellar/ruby-xdr/pull/13])

* Fix .from_xdr encoding param to accept symbols
  ((#14)[https://github.com/stellar/ruby-xdr/pull/14])