raop: Use correct auth type for RAOP pairing

[postlund]

Fixes #2092

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.02 :tada:

Comparison is base (a01117d) 88.83% compared to head (09620bd) 88.85%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #2093 +/- ## ========================================== + Coverage 88.83% 88.85% +0.02% ========================================== Files 162 162 Lines 10863 10858 -5 ========================================== - Hits 9650 9648 -2 + Misses 1213 1210 -3 ``` | [Impacted Files](https://app.codecov.io/gh/postlund/pyatv/pull/2093?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Pierre+St%C3%A5hl) | Coverage Δ | | |---|---|---| | [pyatv/protocols/airplay/pairing.py](https://app.codecov.io/gh/postlund/pyatv/pull/2093?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Pierre+St%C3%A5hl#diff-cHlhdHYvcHJvdG9jb2xzL2FpcnBsYXkvcGFpcmluZy5weQ==) | `96.15% <100.00%> (ø)` | | | [pyatv/protocols/raop/\_\_init\_\_.py](https://app.codecov.io/gh/postlund/pyatv/pull/2093?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Pierre+St%C3%A5hl#diff-cHlhdHYvcHJvdG9jb2xzL3Jhb3AvX19pbml0X18ucHk=) | `96.96% <100.00%> (+1.43%)` | :arrow_up: | ... and [1 file with indirect coverage changes](https://app.codecov.io/gh/postlund/pyatv/pull/2093/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Pierre+St%C3%A5hl)

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