mw/file: rename to BenchmarkFileLookup (#741)

In grafana we miss the context of where this is called, make the name
more descriptive.

Also test the GH webhook.

middleware/file/file_test.go

@@ -5,7 +5,7 @@ import (
 	"testing"
 )
 
-func BenchmarkParseInsert(b *testing.B) {
+func BenchmarkFileParseInsert(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		Parse(strings.NewReader(dbMiekENTNL), testzone, "stdin", 0)
 	}