Bump version to 16.0.19 for the Oracle (OCI) dbFetch fix (tam#35892)

16.0.18 binaries were already published to download2 and contain the
ROracle::dbFetch defect, which breaks every Oracle (OCI) query. Publishing under
a new version rather than overwriting, because upload_packages.sh moves with
mv -n and would silently discard a same-named replacement.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: hidekoji

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: exploratory
 Type: Package
 Title: R package for Exploratory
-Version: 16.0.18
+Version: 16.0.19
 Date: 2026-07-28
 Authors@R: c(person("Hideaki", "Hayashi", email = "hideaki@exploratory.io", role = c("aut", "cre")), person("Hide", "Kojima", email = "hide@exploratory.io", role = c("aut")), person("Kan", "Nishida", email = "kan@exploratory.io", role = c("aut")), person("Kei", "Saito", email = "kei@exploratory.io", role = c("aut")), person("Yosuke", "Yasuda", email = "double.y.919.quick@gmail.com", role = c("aut")))
 URL: https://github.com/exploratory-io/exploratory_func