Use cache of packages in build step

[pkqk]

The /go/pkg/mod cache was not being referenced in the build step so the modules were being downloaded twice.

[codecov-commenter]

Codecov Report

Patch and project coverage have no change.

Comparison is base (87f96c5) 71.06% compared to head (cd5407c) 71.06%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #222 +/- ## ======================================= Coverage 71.06% 71.06% ======================================= Files 27 27 Lines 2737 2737 ======================================= Hits 1945 1945 Misses 670 670 Partials 122 122 ```

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