fix update attributes

[tanhauhau]

• to have helmetAttributes and attributesToRemove separately is a bit unnecessary IMHO

[codecov]

Codecov Report

Merging #369 into master will decrease coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #369      +/-   ##
==========================================
- Coverage    97.6%   97.58%   -0.02%     
==========================================
  Files           3        3              
  Lines         292      290       -2     
==========================================
- Hits          285      283       -2     
  Misses          7        7

Impacted Files	Coverage Δ
src/HelmetUtils.js	96.84% <100%> (-0.03%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update c102586...3b22583. Read the comment docs.