CompatHelper: bump compat for FillArrays to 1, (keep existing compat)

[github-actions[bot]]

This pull request changes the compat entry for the FillArrays package from 0.12, 0.13 to 0.12, 0.13, 1. This keeps the compat entries for earlier versions.

Note: I have not tested your package with this new compat entry. It is your responsibility to make sure that your package tests pass before you merge this pull request.

[codecov[bot]]

Codecov Report

Patch and project coverage have no change.

Comparison is base (82999e6) 93.35% compared to head (79c26da) 93.35%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #143 +/- ## ======================================= Coverage 93.35% 93.35% ======================================= Files 4 4 Lines 286 286 ======================================= Hits 267 267 Misses 19 19 ``` Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=JuliaGaussianProcesses). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=JuliaGaussianProcesses)

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