Add types for httpSecurityHeaders

[crespowang]

I noticed the types for httpSecurityHeaders is added in 1.0.0-alpha but not master, so just do it to make it work for now.

[codecov]

Codecov Report

Merging #302 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##           master   #302   +/-   ##
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  Coverage     100%   100%           
=====================================
  Files          19     19           
  Lines         511    511           
  Branches      105    105           
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  Hits          511    511

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[codecov]

Codecov Report

Merging #302 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##           master   #302   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files          19     19           
  Lines         511    511           
  Branches      105    105           
=====================================
  Hits          511    511

---

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 c464859...7e18286. Read the comment docs.

[lmammino]

Thanks, seems great at a first glance. I'll review this better and get it merged in the next few hours :)