add StructTypes.jl support

[codecov-commenter]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.20% :tada:

Comparison is base (2223432) 95.09% compared to head (c90e886) 95.29%. Report is 1 commits behind head on master.

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #8 +/- ## ========================================== + Coverage 95.09% 95.29% +0.20% ========================================== Files 1 1 Lines 163 170 +7 ========================================== + Hits 155 162 +7 Misses 8 8 ``` | [Files Changed](https://app.codecov.io/gh/jw3126/StructHelpers.jl/pull/8?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Jan+Weidner) | Coverage Δ | | |---|---|---| | [src/StructHelpers.jl](https://app.codecov.io/gh/jw3126/StructHelpers.jl/pull/8?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Jan+Weidner#diff-c3JjL1N0cnVjdEhlbHBlcnMuamw=) | `95.29% <100.00%> (+0.20%)` | :arrow_up: |

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