fix typo in code snippet

[jgravois]

the extra asterisk causes this:

[codecov]

Codecov Report

Merging #493 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##           master   #493   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files          94     94           
  Lines        1208   1208           
  Branches      225    225           
=====================================
  Hits         1208   1208

Impacted Files	Coverage Δ
...ckages/arcgis-rest-request/src/utils/get-portal.ts	100% <ø> (ø)	⬆️

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