add .bench-env to gitignore

Signed-off-by: Connor Tsui <connor.tsui20@gmail.com>

Author: connortsui20

.gitignore

@@ -244,4 +244,4 @@ trace*.pb
 vortex-python/.benchmarks/
 # For local benchmarks website server and things like the WAL
 **.duckdb*
-
+.bench-env