Use Netty 4.1.68 which fixes CVE-2021-37136 and CVE-2021-37137

[dlvenable]

Description

Fixes two CVEs which are in the currently used version of Netty.

See https://netty.io/news/2021/09/09/4-1-68-Final.html

Issues Resolved

N/A

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[codecov-commenter]

Codecov Report

❗ No coverage uploaded for pull request base (1.2@3eb5f2e). Click here to learn what that means.
The diff coverage is n/a.

@@          Coverage Diff           @@
##             1.2     #661   +/-   ##
======================================
  Coverage       ?   91.38%           
  Complexity     ?      583           
======================================
  Files          ?       74           
  Lines          ?     1788           
  Branches       ?      148           
======================================
  Hits           ?     1634           
  Misses         ?      116           
  Partials       ?       38           

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