add fargate service quotas

[robpickerill]

This PR adds fargate service quotas discovery (not the ECS service quotas as they aren't yet supported in the service quota API).

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[codecov-commenter]

Codecov Report

Merging #532 (683118e) into develop (8921393) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##           develop      #532   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           42        42           
  Lines         3021      3022    +1     
  Branches       451       451           
=========================================
+ Hits          3021      3022    +1     

Impacted Files	Coverage Δ
awslimitchecker/services/ecs.py	100.00% <100.00%> (ø)

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[jantman]

This has been released in 12.0.0, which is now live on PyPI and Docker Hub. Thank you so much!