message: Provide an alternative method to find gRPC `roots.pem` file, using an environment
  variable, to avoid having to copy a particular file to `/usr/share`.
diff: @@ -324,8 +324,14 @@ If you encounter a log line that includes the following:
  "filename":"/usr/share/grpc/roots.pem"
  ```
  -you likely need to copy the [gRPC `roots.pem` file][grpcPem] to
  -`/usr/share/grpc/roots.pem` on your local machine.
  +you can solve it via either of the following approaches:
  +
  +* copy the [gRPC `roots.pem` file][grpcPem] to
  + `/usr/share/grpc/roots.pem` on your local machine, which is the default
  + location where gRPC will look for this file
  +* export the environment variable `GRPC_DEFAULT_SSL_ROOTS_FILE_PATH` to point to
  + the full path of the gRPC `roots.pem` file on your file system if it's in a
  + different location
  [grpcPem]: https://github.com/grpc/grpc/blob/master/etc/roots.pem
  