Bump flatten-maven-plugin from 1.3.0 to 1.4.0 (#48)

Bumps [flatten-maven-plugin](https://github.com/mojohaus/flatten-maven-plugin) from 1.3.0 to 1.4.0.
- [Release notes](https://github.com/mojohaus/flatten-maven-plugin/releases)
- [Commits](mojohaus/flatten-maven-plugin@flatten-maven-plugin-1.3.0...1.4.0)

---
updated-dependencies:
- dependency-name: org.codehaus.mojo:flatten-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

pom.xml

@@ -445,7 +445,7 @@
     <docs-maven-skin.version>2.3.2</docs-maven-skin.version>
     <enforcer-plugin.version>3.2.1</enforcer-plugin.version>
     <failsafe-plugin.version>2.22.2</failsafe-plugin.version>
-    <flatten-plugin.version>1.3.0</flatten-plugin.version>
+    <flatten-plugin.version>1.4.0</flatten-plugin.version>
     <hamcrest.version>2.2</hamcrest.version>
     <info-reports-plugin.version>3.4.2</info-reports-plugin.version>
     <jacoco-plugin.version>0.8.8</jacoco-plugin.version>