Adjustments for BUNDLE group. Update ex_ice.

[mickel8]

Besides fixes listed below, this PR also update deps and adjusts code to the newest ex_ice.

Fixes:

• an m-line is only rejected when it has port set to 0 and there is no bundle-only attribute, see here. This is used by Firefox when PC is configured with bundlePolicy: "maxBundle"
• rejected m-lines are not included in the BUNDLE group, see here
• in maxBundle policy (the only one we support), candidates are only included in the first m-line, see here. This seems to be true even if the first m-line is stopped in subsequent offers, at least until ICE restart, which I left untouched i.e. we always include candidates in the first mline

Questionable:

• in maxBundle policy, all mlines but the first one should have bundle-only attribute added, and port in the m-section set to 0, see here. However, there are differences between JSEP RFC, BUNDLE RFC, and browser implementations (see RFC 8829. sec. 1.3 and because of that, we still don't use neither port 0 nor bundle-only attribute

• depending on the bundle-policy, browsers may send candidates for every m-section, only for the first m-section, or for every type of m-section. There is a question, which candidates we should add to the ICE agent on the answerer side (as we only have one ICE stream and one ICE component) - all of them or only those from the first m-section. Looking at RFC 8829, sec. 5.11:

  If the answer contains valid bundle groups, discard any ICE components for the "m=" sections that will be bundled onto the primary ICE components in each bundle, and begin muxing these "m=" sections accordingly, as described in [RFC8843], Section 7.4.

  so we could take only those candidates that belong to the first m-section as other ICE components on the offerer side should be closed anyway. However, because current solution seems to work, I would go back to this question once we notice any problems.

• depending on the rtcpMuxPolicy browsers may generate candidates only for one ICE component (RTP) or for two ICE components (RTP and RTCP) doubling the number of ICE candidates. There is the same question as in the point above, and we do exactly the same thing i.e. we add all candidates regardless of their ICE components.

[codecov[bot]]

Codecov Report

Merging #102 (a45b08a) into master (37db947) will increase coverage by 0.06%. The diff coverage is 95.00%.

:exclamation: Current head a45b08a differs from pull request most recent head 4f726fc. Consider uploading reports for the commit 4f726fc to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #102 +/- ## ========================================== + Coverage 87.13% 87.20% +0.06% ========================================== Files 33 33 Lines 1625 1626 +1 ========================================== + Hits 1416 1418 +2 + Misses 209 208 -1 ``` | [Files](https://app.codecov.io/gh/elixir-webrtc/ex_webrtc/pull/102?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc) | Coverage Δ | | |---|---|---| | [lib/ex\_webrtc/peer\_connection.ex](https://app.codecov.io/gh/elixir-webrtc/ex_webrtc/pull/102?src=pr&el=tree&filepath=lib%2Fex_webrtc%2Fpeer_connection.ex&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc#diff-bGliL2V4X3dlYnJ0Yy9wZWVyX2Nvbm5lY3Rpb24uZXg=) | `82.52% <100.00%> (-0.04%)` | :arrow_down: | | [lib/ex\_webrtc/peer\_connection/configuration.ex](https://app.codecov.io/gh/elixir-webrtc/ex_webrtc/pull/102?src=pr&el=tree&filepath=lib%2Fex_webrtc%2Fpeer_connection%2Fconfiguration.ex&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc#diff-bGliL2V4X3dlYnJ0Yy9wZWVyX2Nvbm5lY3Rpb24vY29uZmlndXJhdGlvbi5leA==) | `91.66% <ø> (+2.33%)` | :arrow_up: | | [lib/ex\_webrtc/sdp\_utils.ex](https://app.codecov.io/gh/elixir-webrtc/ex_webrtc/pull/102?src=pr&el=tree&filepath=lib%2Fex_webrtc%2Fsdp_utils.ex&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc#diff-bGliL2V4X3dlYnJ0Yy9zZHBfdXRpbHMuZXg=) | `91.72% <92.85%> (-0.46%)` | :arrow_down: | ------ [Continue to review full report in Codecov by Sentry](https://app.codecov.io/gh/elixir-webrtc/ex_webrtc/pull/102?dropdown=coverage&src=pr&el=continue&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc). > **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc) > `Δ = absolute (impact)`, `ø = not affected`, `? = missing data` > Powered by [Codecov](https://app.codecov.io/gh/elixir-webrtc/ex_webrtc/pull/102?dropdown=coverage&src=pr&el=footer&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc). Last update [37db947...4f726fc](https://app.codecov.io/gh/elixir-webrtc/ex_webrtc/pull/102?dropdown=coverage&src=pr&el=lastupdated&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=elixir-webrtc).