Update to jsbn 1.4.

- Update to `jsbn` 1.4.
- Retrieved from http://www-cs-students.stanford.edu/~tjw/jsbn/.
- Sync partly back to original style for easier updates every decade or
  so.

Author: davidlehn

CHANGELOG.md

@@ -1,6 +1,12 @@
 Forge ChangeLog
 ===============
 
+## 1.4.0 - 2026-xx-xx
+
+### Changed
+- [jsbn] Update to `jsbn` 1.4. Sync partly back to original style for easier
+  updates every decade or so.
+
 ## 1.3.3 - 2025-12-02
 
 ### Fixed