Update ElasticCache default limits

[sebasrp]

Bug Report

When reporting a bug in awslimitchecker, please provide all of the following information,
as well as any additional details that may be useful in reproducing or fixing
the issue:

Version

awslimitchecker 9.0.0

Installation Method

Installed through pipenv and executed through python directly

Supporting Software Versions

➜ pipenv run python --version
Python 3.8.5

➜ pipenv --version
pipenv, version 2020.8.13

➜ sw_vers
ProductName:	Mac OS X
ProductVersion:	10.15.6
BuildVersion:	19G2021

Actual Output

➜ awslimitchecker --region ap-southeast-1 -P pd-staging --service ElastiCache --list-defaults
awslimitchecker 9.0.0@9.0.0 is AGPL-licensed free software; all users have a right to the full source code of this version. See <https://github.com/jantman/awslimitchecker>
WARNING:awslimitchecker.trustedadvisor:Cannot check TrustedAdvisor: AWS Premium Support Subscription is required to use this service.
ElastiCache/Nodes                     100
ElastiCache/Nodes per Cluster         20
ElastiCache/Parameter Groups          20
ElastiCache/Security Groups           50
ElastiCache/Subnet Groups             50
ElastiCache/Subnets per subnet group  20

Expected Output

Based on https://docs.aws.amazon.com/general/latest/gr/elasticache-service.html, these limits are no longer accurate and should be:

Limit	Current Value	New value
ElastiCache/Nodes	100	300
ElastiCache/Nodes per Cluster	20	40 20
ElastiCache/Parameter Groups	20	150
ElastiCache/Security Groups	50
ElastiCache/Subnet Groups	50	150
ElastiCache/Subnets per subnet group	20

TrustedAdvisor

Not Applicable

Testing Assistance

Yes, i will be able to assist in testing pre-release code for the feature.

[sebasrp]

I am preparing a pull request for this update

[FabianSawatzki1234]

We ran into the ElastiCache limits as well and it's a false positve. Please merge the pull request.

[jantman]

Replied to the PR with a question regarding default limits. I'll get it merged this week. Sorry for the delay.

[sebasrp]

Seems like the limits I specified in the description should be these updates instead

Limit	Current Value	New value
ElastiCache/Nodes	100	300
ElastiCache/Nodes per Cluster	20	40 20
ElastiCache/Parameter Groups	20	150
ElastiCache/Security Groups	50
ElastiCache/Subnet Groups	50	150
ElastiCache/Subnets per subnet group	20

[sebasrp]

updated PR to match this.

[jantman]

A fix for this issue has been merged to the develop branch and is slated for release in 10.0.0 on Monday, December 7, 2020. Anyone who is able to test the fix is strongly encouraged to do so, and comment on this issue with their results. Instructions for installing awslimitchecker from a git branch are available in the Installing for Development documentation.

[jantman]

This has been fixed in 10.0.0, which is now live on PyPI and is being built on the Docker hub right now. Thank you so much for the contribution!