message: Fix typo in java JWT example.
diff: @@ -10,7 +10,7 @@ The key material was generated with:
  ```shell
  $ tinkey create-keyset --key-template JWT_ES256 --out-format JSON \
  - --out jwt_test_private_keyset.json
  + --out jwt_signature_test_private_keyset.json
  ```
  ## Build and Run
  @@ -24,10 +24,10 @@ $ bazel build ...
  $ touch token.txt
  $ ./bazel-bin/jwt/jwt_sign \
  - ./jwt/jwt_test_private_keyset.json example_audience token.txt
  + ./jwt/jwt_signature_test_private_keyset.json example_audience token.txt
  $ ./bazel-bin/jwt/jwt_generate_public_jwk_set \
  - ./jwt/jwt_test_private_keyset.json public_jwk_set.json
  + ./jwt/jwt_signature_test_private_keyset.json public_jwk_set.json
  $ ./bazel-bin/jwt/jwt_verify \
  public_jwk_set.json example_audience token.txt
  