fix so that Requires is not getting loaded on 1.9+

[codecov[bot]]

Codecov Report

Patch coverage has no change and project coverage change: -9.98 :warning:

Comparison is base (5c74b62) 82.36% compared to head (bd6ba3a) 72.39%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #261 +/- ## ========================================== - Coverage 82.36% 72.39% -9.98% ========================================== Files 21 21 Lines 828 826 -2 ========================================== - Hits 682 598 -84 - Misses 146 228 +82 ``` | [Impacted Files](https://codecov.io/gh/korsbo/Latexify.jl/pull/261?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Niklas+Korsbo) | Coverage Δ | | |---|---|---| | [src/Latexify.jl](https://codecov.io/gh/korsbo/Latexify.jl/pull/261?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Niklas+Korsbo#diff-c3JjL0xhdGV4aWZ5Lmps) | `36.36% <ø> (+5.59%)` | :arrow_up: | ... and [2 files with indirect coverage changes](https://codecov.io/gh/korsbo/Latexify.jl/pull/261/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Niklas+Korsbo) 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=Niklas+Korsbo). 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=Niklas+Korsbo)

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[KristofferC]

bump @korsbo