Update dependency com.squareup.okio:okio to v3.13.0

[renovate]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
com.squareup.okio:okio	3.11.0 -> 3.13.0

---

Release Notes

square/okio (com.squareup.okio:okio)

v3.13.0

2025-06-13

• New: okio.Socket interface. This is a first step towards low-level streaming networking support
  for Kotlin/Multiplatform. This release provides two JVM-only implementations: asOkioSocket()
  adapts a java.net.Socket to our new interface, and inMemorySocketPair() returns a pair of
  mutually-connected sockets. We also anticipate that this interface will be a useful abstraction
  for proxies and tunnels.
• New: In-development snapshots are now published to the [Central Portal Snapshots repository].

v3.12.0

2025-05-27

• New: Support an optional end index when searching with BufferedSource.indexOf().
• Fix: Don't do unnecessary work in BufferedSource.rangeEquals().
• Upgrade: [Kotlin 2.1.21][kotlin_2_1_21].

---

• If you want to rebase/retry this PR, check this box

---

This PR was generated by Mend Renovate. View the repository job log.