Bumping version to 0.4.0 and removing the dead links in the Changelog.

CHANGELOG.md

@@ -3,7 +3,9 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
-## [Unreleased]
+## [Unreleased](https://github.com/dennisstritzke/ipsec_exporter/compare/v0.4.0...HEAD)
+
+## [0.4.0](https://github.com/dennisstritzke/ipsec_exporter/releases/tag/v0.4.0) - 2021-09-03
 ### Added
 - `--enable.sudo` command line options, which causes the exporter to prefix the `ipsec statusall`-call with `sudo`. (#23)
 
@@ -66,10 +68,3 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ### Added
 - Detection of configured IPsec tunnels by reading the `ipsec.conf` file.
 - Prometheus metrics, indicate if the tunnel is up, the connection is up or the tunnel is down.
-
-[Unreleased]: https://github.com/dennisstritzke/ipsec_exporter/compare/v0.3...HEAD
-[0.3]: https://github.com/dennisstritzke/ipsec_exporter/compare/v0.2...v0.3
-[0.2]: https://github.com/dennisstritzke/ipsec_exporter/compare/v0.1.2.1...v0.2
-[0.1.2.1]: https://github.com/dennisstritzke/ipsec_exporter/compare/v0.1.2...v0.1.2.1
-[0.1.2]: https://github.com/dennisstritzke/ipsec_exporter/compare/v0.1.1...v0.1.2
-[0.1.1]: https://github.com/dennisstritzke/ipsec_exporter/compare/v0.1...v0.1.1