Update tianon/buildkit pin
@@ -1 +1 @@
-sha256:bc52fb7e18a06e5d04c45a82f4ce18b91ade00435b48b4aec9c48883c19c6258
+sha256:bf3219bf3838419d678be38d482b0a083cd8b41034306ac45b79a38e05e5a036