fix: Fix time format for older versions of journalctl

dimonomid · dimonomid · commit 528974d988d6 · 2025-05-11T22:53:20.000+03:00
It was supposed to be already supported, but there was a bug that it was
only working in UTC (so the timestamp had to have the `+0000` suffix),
and didn't work with e.g. `+0200`.
diff --git a/core/parsing_time.go b/core/parsing_time.go
@@ -140,7 +140,7 @@ func DetectTimeLayout(logLine string) string {
 	var knownFormats = []string{
 		"Jan _2 15:04:05",                  // Traditional rsyslog format without year
 		"2006-01-02T15:04:05.000000Z07:00", // ISO8601, used in modern rsyslog by default
-		"2006-01-02T15:04:05.000000+0000",  // Used by journalctl with --output=short-iso-precise
+		"2006-01-02T15:04:05.000000-0700",  // Used by older versions of journalctl with --output=short-iso-precise
 		"2006-01-02 15:04:05",
 		"2006-01-02T15:04:05Z07:00",
 		"2006-01-02T15:04:05.000Z07:00",
