Use info log level when invalid one is provided & Add IMGPROXY_LOG_LEVEL to changelog

CHANGELOG.md

@@ -1,6 +1,8 @@
 # Changelog
 
 ## [Unreleased]
+### Added
+- `IMGPROXY_LOG_LEVEL` config.
 
 ## [2.7.0] - 2019-11-13
 ### Changed

log.go

@@ -24,7 +24,7 @@ func initLog() {
 
 	levelLogLevel, err := logrus.ParseLevel(logLevel)
 	if err != nil {
-		levelLogLevel = logrus.DebugLevel
+		levelLogLevel = logrus.InfoLevel
 	}
 
 	logrus.SetLevel(levelLogLevel)