Bump org.codehaus.mojo:flatten-maven-plugin from 1.6.0 to 1.7.3

Bumps [org.codehaus.mojo:flatten-maven-plugin](https://github.com/mojohaus/flatten-maven-plugin) from 1.6.0 to 1.7.3.
- [Release notes](https://github.com/mojohaus/flatten-maven-plugin/releases)
- [Commits](mojohaus/flatten-maven-plugin@1.6.0...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]

assembly-thin/pom.xml

@@ -64,7 +64,7 @@
             <plugin>
                 <groupId>org.codehaus.mojo</groupId>
                 <artifactId>flatten-maven-plugin</artifactId>
-                <version>1.6.0</version>
+                <version>1.7.3</version>
                 <configuration>
                     <updatePomFile>true</updatePomFile>
                     <flattenMode>oss</flattenMode>

assembly-uber/pom.xml

@@ -64,7 +64,7 @@
             <plugin>
                 <groupId>org.codehaus.mojo</groupId>
                 <artifactId>flatten-maven-plugin</artifactId>
-                <version>1.6.0</version>
+                <version>1.7.3</version>
                 <configuration>
                     <updatePomFile>true</updatePomFile>
                     <flattenMode>oss</flattenMode>