cmd/gendb: rename by-ID directory

Rename from "byID" to "ID".

Change-Id: I51f07a4fe85255579e59754c7b9ad8b23d269ed2
Reviewed-on: https://go-review.googlesource.com/c/vulndb/+/356150
Trust: Jonathan Amsterdam <jba@google.com>
Run-TryBot: Jonathan Amsterdam <jba@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Julie Qiu <julie@golang.org>
diff --git a/cmd/gendb/main.go b/cmd/gendb/main.go
index 0d175a4..065df03 100644
--- a/cmd/gendb/main.go
+++ b/cmd/gendb/main.go
@@ -114,7 +114,7 @@
 	}
 
 	// Write a directory containing entries by ID.
-	idDir := filepath.Join(*jsonDir, "byID")
+	idDir := filepath.Join(*jsonDir, "ID")
 	if err := os.MkdirAll(idDir, 0700); err != nil {
 		failf("failed to create directory %q: %v", idDir, err)
 	}