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/blang/semver/sql.go

@@ -0,0 +1,30 @@
+package semver
+
+import (
+	"database/sql/driver"
+	"fmt"
+)
+
+// Scan implements the database/sql.Scanner interface.
+func (v *Version) Scan(src interface{}) (err error) {
+	var str string
+	switch src := src.(type) {
+	case string:
+		str = src
+	case []byte:
+		str = string(src)
+	default:
+		return fmt.Errorf("Version.Scan: cannot convert %T to string.", src)
+	}
+
+	if t, err := Parse(str); err == nil {
+		*v = t
+	}
+
+	return
+}
+
+// Value implements the database/sql/driver.Valuer interface.
+func (v Version) Value() (driver.Value, error) {
+	return v.String(), nil
+}