feat(eslint-plugin): [consistent-type-assertions] always allow const assertions

[garyking]

The consistent-type-assertions rule should always allow as const, as it is beneficial, per the official TypeScript docs.

Closes #992.

[garyking]

@bradzacher Anything I can do to help move this PR along? 🙂

[bradzacher]

It's in the review queue.

https://github.com/typescript-eslint/typescript-eslint/pulls?q=is%3Apr+is%3Aopen+sort%3Acreated-asc+-label%3A%22breaking+change%22+-label%3A%22awaiting+response%22+-label%3A%221+approval%22+-label%3A%22DO+NOT+MERGE%22+-author%3Abradzacher

I just need to find time to get to it.

[bradzacher]

ezpz thanks for this

[codecov]

Codecov Report

Merging #1713 into master will decrease coverage by 0.00%.
The diff coverage is 85.71%.

@@            Coverage Diff             @@
##           master    #1713      +/-   ##
==========================================
- Coverage   94.49%   94.48%   -0.01%     
==========================================
  Files         162      162              
  Lines        7481     7487       +6     
  Branches     2143     2146       +3     
==========================================
+ Hits         7069     7074       +5     
  Misses        178      178              
- Partials      234      235       +1     

Flag	Coverage Δ
#unittest	94.48% <85.71%> (-0.01%)	⬇️

Impacted Files	Coverage Δ
...int-plugin/src/rules/consistent-type-assertions.ts	86.48% <85.71%> (-0.62%)	⬇️