Add toolbar as a valid Open Parameter

[cancan101]

Fom https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/pdf_open_parameters.pdf:

toolbar=1|0 Turns the toolbar on or off.

From testing and from https://stackoverflow.com/questions/2104608/hiding-the-toolbars-surrounding-an-embedded-pdf, this also works on Chrome.

[codecov-commenter]

Codecov Report

Merging #106 into master will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #106   +/-   ##
=======================================
  Coverage   90.00%   90.00%           
=======================================
  Files           2        2           
  Lines          20       20           
  Branches        3        3           
=======================================
  Hits           18       18           
  Misses          2        2           

Impacted Files	Coverage Δ
src/index.tsx	87.50% <ø> (ø)

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