Fix deprecation in `WebSocketClient`

This patch was authored by @axtonpitt and released by @0xTim.

Fix TLSConfiguration.forClient() deprecation warning

warning: 'forClient(cipherSuites:minimumTLSVersion:maximumTLSVersion:certificateVerification:trustRoots:certificateChain:privateKey:applicationProtocols:shutdownTimeout:keyLogCallback:)' is deprecated: renamed to 'makeClientConfiguration()'

Fix issue where web sockets don't close on TLS connections

This patch was authored by @EthanLozano and released by @0xTim.

Resolves an issue where web socket connections weren't being closed after being sent a close() from the client on TLS connections (#89). Resolves (#86)

Fix miscellaneous issues with WebSocket closing

This patch was authored by @tanner0101 and released by @siemensikkema.

Fixes miscellaneous issues with regards to closing a WebSocket connection (#77)

Fix force try in connect method

This patch was authored by @jameshartt and released by @tanner0101.

Fix force try in wss:// connect method (#71).

Automatic WebSocket pings

This patch was authored by @bridger and released by @tanner0101.

Adds a pingInterval property on WebSocket which will trigger automatic pings to the peer to ensure that the connection is still active (#68).

Send correct close code to peer

This patch was authored by @bridger and released by @tanner0101.

Updates WebSocket close to send correct code to peer according to RFC6455 (#67).

WebSocketKit 2.0.0

Docs:
https://docs.vapor.codes/4.0/websockets/

More information on Vapor 4 official release:
https://forums.swift.org/t/vapor-4-official-release-begins/34802

Release Candidate 1

Updates to Swift 5.2 and macOS 10.15. Adds additional CI + README updates.

Release candidates represent the final shift toward focusing on bug fixes and documentation. Breaking changes will only be accepted for critical issues. We expect a final release of this package shortly after Swift 5.2's release date.

Add errorCaught handler to close the WebSocket

Now when an error is thrown by NIO we receive it and close the WebSocket connection. The error code is available on WebSocket.closeCode by the time the WebSocket.onClose future resolves (#61, fixes #58).

Add channelInactive callback to mark WebSocket as closed.

The channelInactive callback is triggered when a WebSocket closes without sending a close code. Previously, the WebSocket.onClose future was still fulfilled but WebSocket.isClosed would be false and WebSocket.closeCode would be nil. This would later cause an assertion when WebSocket deinitialized. Now the onClose future is still fulfilled, but while also setting isClosed and closeCode (#60, fixes vapor/vapor#2107).