use istio client-go library instead of knative (#1661)

use istio client-go library instead of knative
bump kubernetes dependency version
change code coverage to codecov

vendor/github.com/sirupsen/logrus/terminal_check_bsd.go

@@ -0,0 +1,13 @@
+// +build darwin dragonfly freebsd netbsd openbsd
+
+package logrus
+
+import "golang.org/x/sys/unix"
+
+const ioctlReadTermios = unix.TIOCGETA
+
+func isTerminal(fd int) bool {
+	_, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
+	return err == nil
+}
+