Bump ikonli-materialdesign2-pack from 12.3.0 to 12.3.1

Bumps [ikonli-materialdesign2-pack](https://github.com/kordamp/ikonli) from 12.3.0 to 12.3.1.
- [Release notes](https://github.com/kordamp/ikonli/releases)
- [Changelog](https://github.com/kordamp/ikonli/blob/master/jreleaser.yml)
- [Commits](kordamp/ikonli@v12.3.0...v12.3.1)

---
updated-dependencies:
- dependency-name: org.kordamp.ikonli:ikonli-materialdesign2-pack
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

build.gradle

@@ -161,7 +161,7 @@ dependencies {
 
     // JavaFX stuff
     implementation 'org.kordamp.ikonli:ikonli-javafx:12.3.0'
-    implementation 'org.kordamp.ikonli:ikonli-materialdesign2-pack:12.3.0'
+    implementation 'org.kordamp.ikonli:ikonli-materialdesign2-pack:12.3.1'
     implementation 'de.saxsys:mvvmfx-validation:1.9.0-SNAPSHOT'
     implementation 'de.saxsys:mvvmfx:1.8.0'
     implementation 'com.tobiasdiez:easybind:2.2'