Fix SQS visibility timeout

Fix setting item visibility timeout (#131)

I am unsure why it happened now. Was it introduced in DispatchRider 2.0 or 2.1 ? 
Was it a change upstream in aws-sdk-sqs ?

* test using `ensure`, because item.visibility_timeout krash

* use change visibility

* make aws sns/sqs required runtime gem

* fix openstruct in specs

* use a proc

* require gems, do not rescue NameError exceptions

* bump version

* stub object for the method call instead

* rubocop

Ruby 3 support

v2.1.0 (2022-09-20)

Full Changelog

• Added support for ruby 3.0 and 3.1
• Require ruby 2.7 at the very minimum, there is a meta-programming class with kwargs between 2.6 and 3.0
  since 2.6 is not unsupported, support is removed

Rails 6 and 7 support, aws-sdk 3.x, clean up

v2.0.0 (2022-09-20)

Full Changelog

• Tests now run via Github actions
• Requires Ruby 2.6.5 at the very minimum
• Requires Rails 5.2 at the very minimum
• Supports both Aws SDK 1.x and 3.x
• aws-sdk-sqs and aws-sdk-sns are marked as optional, but strongly recommended.
• Security Update Rails (CVE-2022-32224): Automatically set the active-record config DispatchRider::ScheduledJob model.
• Tests are validated against rails 5.2.x, 6.0.x, 6.1.x and 7.0.x
• Started addressing some of the style issue and tech debt via rubocop-challenger automated PR

v1.9.0: Merge pull request #77 from payrollhero/wait-one-sec

lets wait a second

v1.8.6: Merge pull request #76 from payrollhero/travis

• ruby 2.1 support dropped
• appsignal gem now optional
• we use retriable gem instead of retries gem