Replace deprecated ioutil funcs with io

[pkqk]

ioutil has been deprecated and equivalent methods are in the io package now.

[codecov-commenter]

Codecov Report

Base: 70.80% // Head: 70.80% // No change to project coverage :thumbsup:

Coverage data is based on head (bc6564e) compared to base (cf2f07f). Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #184 +/- ## ======================================= Coverage 70.80% 70.80% ======================================= Files 26 26 Lines 2699 2699 ======================================= Hits 1911 1911 Misses 665 665 Partials 123 123 ``` | [Impacted Files](https://codecov.io/gh/movio/bramble/pull/184?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=movio) | Coverage Δ | | |---|---|---| | [middleware.go](https://codecov.io/gh/movio/bramble/pull/184/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=movio#diff-bWlkZGxld2FyZS5nbw==) | `85.24% <100.00%> (ø)` | | 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=movio). 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=movio)

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