add warning log level

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

internal/log/log.go

@@ -8,6 +8,18 @@ func Errorf(format string, args ...interface{}) {
 	Log.Errorf(format, args...)
 }
 
+func Error(args ...interface{}) {
+	Log.Error(args...)
+}
+
+func Warnf(format string, args ...interface{}) {
+	Log.Warnf(format, args...)
+}
+
+func Warn(args ...interface{}) {
+	Log.Warn(args...)
+}
+
 func Infof(format string, args ...interface{}) {
 	Log.Infof(format, args...)
 }

internal/log/nop.go

@@ -3,6 +3,9 @@ package log
 type nopLogger struct{}
 
 func (l *nopLogger) Errorf(format string, args ...interface{}) {}
+func (l *nopLogger) Error(args ...interface{})                 {}
+func (l *nopLogger) Warnf(format string, args ...interface{})  {}
+func (l *nopLogger) Warn(args ...interface{})                  {}
 func (l *nopLogger) Infof(format string, args ...interface{})  {}
 func (l *nopLogger) Info(args ...interface{})                  {}
 func (l *nopLogger) Debugf(format string, args ...interface{}) {}