Adopt Go 1.18

[tri-adam]

Bump Go versions used in CI to 1.17 and 1.18.

[codecov-commenter]

Codecov Report

Merging #62 (be7fc1f) into master (b907ddc) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #62   +/-   ##
=======================================
  Coverage   91.38%   91.38%           
=======================================
  Files           4        4           
  Lines         209      209           
=======================================
  Hits          191      191           
  Misses         12       12           
  Partials        6        6           

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