Fix bazel location of testdata

Author: spiffxp

test/conformance/README.md

@@ -9,7 +9,7 @@ To update the list, run
 
 ```console
 bazel build //test/conformance:list_conformance_tests
-cp bazel-genfiles/test/conformance/conformance.yaml test/conformance/testdata
+cp bazel-bin/test/conformance/conformance.yaml test/conformance/testdata
 ```
 
 Add the changed file to your PR, then send for review.