upgrade Gandi libdns to 1.0.3

[nustiueudinastea]

upgraded to the latest version of gandi libdns, which fixes an issue where new records could not be created

See https://github.com/foxcpp/maddy/issues/619

[codecov-commenter]

Codecov Report

Attention: 15 lines in your changes are missing coverage. Please review.

Comparison is base (d8232a4) 52.49% compared to head (08671bc) 52.43%. Report is 1 commits behind head on master.

Files	Patch %	Lines
internal/libdns/gandi.go	0.00%	11 Missing :warning:
internal/libdns/provider_module.go	0.00%	4 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #673 +/- ## ========================================== - Coverage 52.49% 52.43% -0.06% ========================================== Files 128 128 Lines 13311 13324 +13 ========================================== Hits 6987 6987 - Misses 5667 5680 +13 Partials 657 657 ``` | [Flag](https://app.codecov.io/gh/foxcpp/maddy/pull/673/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Max+Mazurov) | Coverage Δ | | |---|---|---| | [integration](https://app.codecov.io/gh/foxcpp/maddy/pull/673/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Max+Mazurov) | `34.08% <0.00%> (-0.04%)` | :arrow_down: | | [unit](https://app.codecov.io/gh/foxcpp/maddy/pull/673/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Max+Mazurov) | `53.86% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Max+Mazurov#carryforward-flags-in-the-pull-request-comment) to find out more.

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[foxcpp]

Thanks for your work!