Fix maximum packet count handling

[at-wat]

Accoring to RFC3711 section 9.2, SRTP/SRTCP session must not wrap SRTP ROC and SRTCP index without changing the master key.

ref: https://www.rfc-editor.org/rfc/rfc3711#section-9.2

[codecov[bot]]

Codecov Report

Base: 76.31% // Head: 76.56% // Increases project coverage by +0.24% :tada:

Coverage data is based on head (66c2660) compared to base (a33fda5). Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #222 +/- ## ========================================== + Coverage 76.31% 76.56% +0.24% ========================================== Files 17 17 Lines 1220 1233 +13 ========================================== + Hits 931 944 +13 Misses 198 198 Partials 91 91 ``` | Flag | Coverage Δ | | |---|---|---| | go | `76.56% <100.00%> (+0.24%)` | :arrow_up: | | wasm | `76.07% <100.00%> (+0.25%)` | :arrow_up: | 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=pion#carryforward-flags-in-the-pull-request-comment) to find out more. | [Impacted Files](https://codecov.io/gh/pion/srtp/pull/222?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pion) | Coverage Δ | | |---|---|---| | [errors.go](https://codecov.io/gh/pion/srtp/pull/222/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pion#diff-ZXJyb3JzLmdv) | `100.00% <ø> (ø)` | | | [context.go](https://codecov.io/gh/pion/srtp/pull/222/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pion#diff-Y29udGV4dC5nbw==) | `88.52% <100.00%> (ø)` | | | [option.go](https://codecov.io/gh/pion/srtp/pull/222/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pion#diff-b3B0aW9uLmdv) | `100.00% <100.00%> (ø)` | | | [srtcp.go](https://codecov.io/gh/pion/srtp/pull/222/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pion#diff-c3J0Y3AuZ28=) | `85.48% <100.00%> (+1.00%)` | :arrow_up: | | [srtp.go](https://codecov.io/gh/pion/srtp/pull/222/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pion#diff-c3J0cC5nbw==) | `89.28% <100.00%> (+2.05%)` | :arrow_up: | 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=pion). 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=pion)

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[at-wat]

Going to merge this but feel free to add comments later