Bump org.codehaus.mojo:flatten-maven-plugin from 1.1.0 to 1.7.3

Bumps [org.codehaus.mojo:flatten-maven-plugin](https://github.com/mojohaus/flatten-maven-plugin) from 1.1.0 to 1.7.3.
- [Release notes](https://github.com/mojohaus/flatten-maven-plugin/releases)
- [Commits](mojohaus/flatten-maven-plugin@flatten-maven-plugin-1.1.0...1.7.3)

---
updated-dependencies:
- dependency-name: org.codehaus.mojo:flatten-maven-plugin
  dependency-version: 1.7.3
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

pom.xml

@@ -1089,7 +1089,7 @@
     <version.plugin.maven.source>3.3.1</version.plugin.maven.source>
     <version.plugin.maven.surefire>3.5.4</version.plugin.maven.surefire>
     <version.plugin.mojo.build-helper>3.6.1</version.plugin.mojo.build-helper>
-    <version.plugin.mojo.flatten>1.1.0</version.plugin.mojo.flatten>
+    <version.plugin.mojo.flatten>1.7.3</version.plugin.mojo.flatten>
     <version.plugin.sonatype.central-publishing>0.9.0</version.plugin.sonatype.central-publishing>
     <version.plugin.io.wcm.devops.eclipse>3.2.0</version.plugin.io.wcm.devops.eclipse>
     <version.plugin.eluder.coveralls>4.3.0</version.plugin.eluder.coveralls>