message: docs: remove reference to stamped build from bazel README
diff: @@ -327,7 +327,7 @@ They should also ignore any local `.bazelrc` for reproducibility. This can be
  achieved with:
  ```
  -bazel --bazelrc=/dev/null build -c opt //source/exe:envoy-static.stripped.stamped
  +bazel --bazelrc=/dev/null build -c opt //source/exe:envoy-static.stripped
  ```
  One caveat to note is that the Git SHA1 is truncated to 16 bytes today as a
  