Merge pull request logstash-plugins#164 from karenzone/Fix-link-forma…

…tting

Fix formatting for link

Merge pull request logstash-plugins#163 from yaauie/release-3.4.0

bump version for 3.4.0 release

Version bump to 3.3.7

And changelog update

Fixes logstash-plugins#157

Version bump to 3.3.6

Also updated changelog

Fixes logstash-plugins#156

Version Bump

Also, use SPDX license identifier in gemspec to avoid warning while
building gem

Fixes logstash-plugins#151

Version Bump

Fixes logstash-plugins#150

Symbolize additional_settings hash

AWS SDK expects symbolized hash keys, so do that.

Fixes logstash-plugins#148

Fixes logstash-plugins#149

set default_codec doc attribute

Improve error handling when listing/downloading from S3

Add error checking to:
  Stop plugin from crashing when S3 service errors occur when listing
    the contents of buckets, or downloading files.
  Add log messages when buckets cannot be list/files cannot be downloaded

The error checking should allow the plugin to recover if the error conditions
occur while not blocking progress of handling other items.

This should fix/improve the experience with logstash-plugins#143, logstash-plugins#133 and logstash-plugins#59

Fixes logstash-plugins#144

bump to 3.3.0