net/rustconn: Update to 0.13.6

ChangeLog:

• https://github.com/totoshko88/RustConn/releases/tag/v0.13.0
• https://github.com/totoshko88/RustConn/releases/tag/v0.13.1
• https://github.com/totoshko88/RustConn/releases/tag/v0.13.2
• https://github.com/totoshko88/RustConn/releases/tag/v0.13.3
• https://github.com/totoshko88/RustConn/releases/tag/v0.13.4
• https://github.com/totoshko88/RustConn/releases/tag/v0.13.5
• https://github.com/totoshko88/RustConn/releases/tag/v0.13.6

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