fix(chart): set y domain appropriately

[priley86]

What's included

Set the y-domain according the max y value in the input data...

Related Victory issues:
FormidableLabs/victory#883
https://github.com/FormidableLabs/victory-docs/pull/559/files

How to test

Targets a current edge case where all y values are the same causing the issue noted in Victory charts.

Example data which found this edge case:

{
   "data":[
      {
         "date":"2019-07-25T18:00:09.56Z",
         "instance_count":0,
         "cores":0,
         "sockets":0
      },
      {
         "date":"2019-07-26T00:00:00.696Z",
         "instance_count":0,
         "cores":0,
         "sockets":0
      }
   ],
   "links":{
      "first":"/api/rhsm-subscriptions/v1/tally/products/RHEL?granularity=daily&beginning=2019-06-26T00:00:00.000Z&ending=2019-07-26T23:59:59.999Z&offset=0",
      "last":"/api/rhsm-subscriptions/v1/tally/products/RHEL?granularity=daily&beginning=2019-06-26T00:00:00.000Z&ending=2019-07-26T23:59:59.999Z&offset=0"
   },
   "meta":{
      "count":2,
      "product":"RHEL",
      "granularity":"daily"
   }
}

Coverage and basic unit test check

1. update the NPM packages with $ yarn
2. $ yarn test

Interactive unit test check

1. update the NPM packages with $ yarn
2. $ yarn test:dev
   -->
3. $ yarn test:dev

Example

...

Updates issue/story

Closes #60

[codecov-io]

Codecov Report

Merging #61 into master will increase coverage by 0.31%.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master   #61      +/-   ##
=======================================
+ Coverage   86.68%   87%   +0.31%     
=======================================
  Files          23    23              
  Lines         293   300       +7     
  Branches       60    62       +2     
=======================================
+ Hits          254   261       +7     
  Misses         31    31              
  Partials        8     8

Impacted Files	Coverage Δ
src/common/graphHelpers.js	98.64% <100%> (+0.14%)	⬆️

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[cdcabrera]

Looks good, reviewed some adjustments to the helper, namely

• removed the switch and
• relaxed/removed the linting rule that preferred the shorthand syntax of Math.pow