Log Message:
Update ruby-net-ldap to 0.13.0.

=== Net::LDAP 0.13.0

* Set a connect_timeout for the creation of a socket
  {#243}[https://github.com/ruby-ldap/ruby-net-ldap/pull/243]
* Update bundler before installing gems with bundler
  {#245}[https://github.com/ruby-ldap/ruby-net-ldap/pull/245]
* Net::LDAP#encryption accepts string
  {#239}[https://github.com/ruby-ldap/ruby-net-ldap/pull/239]
* Adds correct UTF-8 encoding to Net::BER::BerIdentifiedString
  {#242}[https://github.com/ruby-ldap/ruby-net-ldap/pull/242]
* Remove 2.3.0-preview since ruby-head already is included
  {#241}[https://github.com/ruby-ldap/ruby-net-ldap/pull/241]
* Drop support for ruby 1.9.3
  {#240}[https://github.com/ruby-ldap/ruby-net-ldap/pull/240]
* Fixed capitalization of StartTLSError
  {#234}[https://github.com/ruby-ldap/ruby-net-ldap/pull/234]