Preparations for v0.8.0

[github-actions]

This PR prepares for the next minor release v0.8.0.

Files that should be automatically modified:

• Cargo.toml (version bump)
  • <crate>/Cargo.toml (version bump)

  for patch versions only the necessary crates will receive an update

• Cargo.lock (only bumps own crate versions)
• CHANGELOG.md (finalize changelog for upcoming version)

Review checklist:

• Confirm the version bump in Cargo.toml is correct
• Ensure Cargo.lock did only update our crates
• Review the changelog for accuracy and completeness

Please verify these changes before merging.

---

After merging, continue by creating a new release with the tag v0.8.0.

See PUBLISHING.md for further infos.

[photovoltex]

Because of 2c20e3b we can't have the same ruleset for the release-prepare branches as this commit violates the Require linear history rule.

See ruleset: https://github.com/librespot-org/librespot/rules/2981869

Snipped:

Pushing pull request branch to 'origin/prepare-release/v0.8.0'
/usr/bin/git push --force-with-lease origin prepare-release/v0.8.0:refs/heads/prepare-release/v0.8.0
remote: error: GH013: Repository rule violations found for refs/heads/prepare-release/v0.8.0.
remote: Review all repository rules at https://github.com/librespot-org/librespot/rules?ref=refs%2Fheads%2Fprepare-release%2Fv0.8.0
remote:
remote: - This branch must not contain merge commits.
remote: Found 1 violation:
remote:
remote: 2c20e3b
remote:
To https://github.com/librespot-org/librespot
! [remote rejected] prepare-release/v0.8.0 -> prepare-release/v0.8.0 (push declined due to repository rule violations)
error: failed to push some refs to 'https://github.com/librespot-org/librespot'
Error: The process '/usr/bin/git' failed with exit code 1

[photovoltex]

Hmm, the release action didn't trigger on release creation like I had hoped... Reading the documentation again can help sometimes. Apparently most events for release fire inconsistent so we need to adjust that then.