docs: stamp v2.0.0 and v1.5.0 release dates in CHANGELOG

The CHANGELOG was left with [Unreleased] and [2.0.0] - TBD
because the version numbers and dates were maintainer decisions.
This commit stamps them:
* v1.5.0 covers PR #40 (P0 quality fixes) and PR #42 (security
  hardening), both backward-compatible.
* v2.0.0 covers PR #44 (invert ssl_verify_certificate default),
  the only breaking change in the v1.x→v2.0.0 line.
* The version comparator links are updated so the [Unreleased]
  link now points at the next v2.0.1+ line.

Author: airvzxf

CHANGELOG.md

@@ -5,7 +5,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [2.0.0] - TBD
+## [2.0.0] - 2026-07-05
 
 ### Breaking
 
@@ -30,7 +30,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   known-insecure default but about the rare case of a user
   explicitly opting back into the v1.x lax behaviour.
 
-## [Unreleased]
+## [1.5.0] - 2026-07-05
+
+Bundles two PRs on top of v1.3.3 with no behaviour change for the
+happy path (all changes are either bug fixes, new optional
+inputs, or hardening that is observable only via exit code 2 on
+malformed input).
 
 ### Added
 - `mirror_verbose` input (was documented in the README but never declared in
@@ -106,6 +111,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 Historical. See git history for changes prior to `CHANGELOG.md` adoption.
 
-[Unreleased]: https://github.com/airvzxf/ftp-deployment-action/compare/v2.0.0...HEAD
-[2.0.0]: https://github.com/airvzxf/ftp-deployment-action/compare/v1.3.3...v2.0.0
+[Unreleased]: https://github.com/airvzxf/ftp-deployment-action/compare/v2.0.1...HEAD
+[2.0.0]: https://github.com/airvzxf/ftp-deployment-action/compare/v1.5.0...v2.0.0
+[1.5.0]: https://github.com/airvzxf/ftp-deployment-action/releases/tag/v1.5.0
 [1.3.3]: https://github.com/airvzxf/ftp-deployment-action/releases/tag/v1.3.3