build(deps): bump github.com/labstack/gommon from 0.3.1 to 0.4.0

Bumps [github.com/labstack/gommon](https://github.com/labstack/gommon) from 0.3.1 to 0.4.0.
- [Release notes](https://github.com/labstack/gommon/releases)
- [Commits](https://github.com/labstack/gommon/compare/v0.3.1...v0.4.0)

---
updated-dependencies:
- dependency-name: github.com/labstack/gommon
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/github.com/labstack/gommon/log/log.go

@@ -391,7 +391,7 @@ func (l *Logger) log(level Lvl, format string, args ...interface{}) {
 		if err == nil {
 			s := buf.String()
 			i := buf.Len() - 1
-			if s[i] == '}' {
+			if i >= 0 && s[i] == '}' {
 				// JSON header
 				buf.Truncate(i)
 				buf.WriteByte(',')
@@ -404,7 +404,9 @@ func (l *Logger) log(level Lvl, format string, args ...interface{}) {
 				}
 			} else {
 				// Text header
-				buf.WriteByte(' ')
+				if len(s) > 0 {
+					buf.WriteByte(' ')
+				}
 				buf.WriteString(message)
 			}
 			buf.WriteByte('\n')