Use tparallel linter

[sevein]

This PR configures the tparallel linter which detects a couple of common mistakes when using t.Parallel().

Context:

• https://github.com/moricho/tparallel
• https://brandur.org/fragments/go-prefer-t-cleanup-with-parallel-subtests

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 48.88%. Comparing base (3102539) to head (4d4aada).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #925 +/- ## ======================================= Coverage 48.88% 48.88% ======================================= Files 103 103 Lines 5533 5533 ======================================= Hits 2705 2705 Misses 2597 2597 Partials 231 231 ```

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