chore: upgrade deps and attempt to enable using go1.19 (#869)

* upgrade to our go.mod enabled of psiphon-tunnel-core such that
we're now using v2.0.24 of the tunnel-core;

* upgrade to the latest lucas-clemente/quic-go release;

* upgrade to the latest ooni/oohttp release (which is based on go1.19
but the diff seems good enough to continue using go1.18.x as well);

* upgrade to the latest ooni/oocrypto release (for which we can make the
same remarks regarding using go1.18.x);

* deal with changes in lucas-clemente/quic-go API as well as changes
in what a go1.19 *tls.Conn compatible type should look like.

Unfortunately, we cannot switch to go1.19 because psiphon forks quic-go
and their fork's still not building using such a version of go.

Part of ooni/probe#2211.

internal/model/mocks/tls_test.go

@@ -60,6 +60,18 @@ func TestTLSConn(t *testing.T) {
 			t.Fatal("not the error we expected", err)
 		}
 	})
+
+	t.Run("NetConn", func(t *testing.T) {
+		conn := &Conn{}
+		c := &TLSConn{
+			MockNetConn: func() net.Conn {
+				return conn
+			},
+		}
+		if o := c.NetConn(); o != conn {
+			t.Fatal("unexpected result")
+		}
+	})
 }
 
 func TestTLSDialer(t *testing.T) {