Adding gosec and lint, fixing null_type overflow

ChangeLog:
  - Adding gosec linting
  - Adding static type to enum
  - fixing nulltype overflow
  - Trying out gotestsum as an alternative to go-junit-report.xml

internal/jet/statement.go

@@ -180,7 +180,7 @@ func duration(f func()) time.Duration {
 
 	f()
 
-	return time.Now().Sub(start)
+	return time.Since(start)
 }
 
 // ExpressionStatement interfacess