Update courier to 0.5.0 and add ssl 4.0.0

Picks up connection hang fixes, SSL fixes, backpressure
fixes, and the macOS FD double-close fix from courier 0.5.0.
Adds ssl as a direct dependency since the project uses
ssl/net types directly.

The new lori (transitive through courier) changed
_on_received to return ReadAction; updated the mock
HTTP server in the test suite to match.

Author: SeanTAllen

corral.json

@@ -10,7 +10,11 @@
     },
     {
       "locator": "github.com/ponylang/courier.git",
-      "version": "0.4.0"
+      "version": "0.5.0"
+    },
+    {
+      "locator": "github.com/ponylang/ssl.git",
+      "version": "4.0.0"
     },
     {
       "locator": "github.com/ponylang/uri.git",

github_rest_api/_test_mock_http_server.pony

@@ -103,10 +103,11 @@ actor \nodoc\ _MockHTTPConnection
   fun ref _connection(): lori.TCPConnection =>
     _tcp_connection
 
-  fun ref _on_received(data: Array[U8] iso) =>
+  fun ref _on_received(data: Array[U8] iso): lori.ReadAction =>
     _buf.append(consume data)
     if _buf.contains("\r\n\r\n") then
       let request: String val = (_buf = String).clone()
       let response = _responder(request)
       _tcp_connection.send(response)
     end
+    lori.KeepReading