Bump com.io7m.xstructural.version from 1.8.1 to 1.9.0

Bumps `com.io7m.xstructural.version` from 1.8.1 to 1.9.0.

Updates `com.io7m.xstructural:com.io7m.xstructural.cmdline` from 1.8.1 to 1.9.0
- [Changelog](https://github.com/io7m-com/xstructural/blob/develop/README-CHANGES.xml)
- [Commits](io7m-com/xstructural@com.io7m.xstructural-1.8.1...com.io7m.xstructural-1.9.0)

Updates `com.io7m.xstructural:com.io7m.xstructural.maven_plugin` from 1.8.1 to 1.9.0
- [Changelog](https://github.com/io7m-com/xstructural/blob/develop/README-CHANGES.xml)
- [Commits](io7m-com/xstructural@com.io7m.xstructural-1.8.1...com.io7m.xstructural-1.9.0)

---
updated-dependencies:
- dependency-name: com.io7m.xstructural:com.io7m.xstructural.cmdline
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: com.io7m.xstructural:com.io7m.xstructural.maven_plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

pom.xml

@@ -33,7 +33,7 @@
     <io7m.java.targetJavaVersion>17</io7m.java.targetJavaVersion>
 
     <!-- io7m dependencies. -->
-    <com.io7m.xstructural.version>1.8.1</com.io7m.xstructural.version>
+    <com.io7m.xstructural.version>1.9.0</com.io7m.xstructural.version>
 
     <!-- Third-party dependencies. -->
     <junit.version>5.11.0</junit.version>