make log level configable (#19)

relatd: https://gitea.com/gitea/act_runner/pulls/39
Reviewed-on: https://gitea.com/gitea/act/pulls/19
Reviewed-by: Jason Song <i@wolfogre.com>
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: a1012112796 <1012112796@qq.com>
Co-committed-by: a1012112796 <1012112796@qq.com>

pkg/runner/runner.go

@@ -59,6 +59,7 @@ type Config struct {
 	ContainerNetworkMode  string                       // the network mode of job containers
 	DefaultActionInstance string                       // the default actions web site
 	PlatformPicker        func(labels []string) string // platform picker, it will take precedence over Platforms if isn't nil
+	JobLoggerLevel        *log.Level                   // the level of job logger
 }
 
 type runnerImpl struct {