Add references to new DynamoDBCache backend

[vonsteer]

What do these changes do?

Add references to new DynamoDBCache backend

Are there changes in behavior for the user?

None

Related issue number

Fixes #937

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.64%. Comparing base (fe28c47) to head (db00583).
Report is 134 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #982      +/-   ##
==========================================
- Coverage   99.76%   99.64%   -0.12%     
==========================================
  Files          36       33       -3     
  Lines        3794     3396     -398     
==========================================
- Hits         3785     3384     -401     
- Misses          9       12       +3     

Flag	Coverage Δ
unit	99.64% <ø> (-0.12%)	⬇️

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