fix(container): update docker.io/library/maven docker tag (3.9.9 → 3.9.12)

| datasource | package                 | from  | to     |
| ---------- | ----------------------- | ----- | ------ |
| docker     | docker.io/library/maven | 3.9.9 | 3.9.12 |

Author: erhardt-consulting-bot

Dockerfile

@@ -1,7 +1,7 @@
 # -----------------------------
 # Stage 1: Maven Build
 # -----------------------------
-FROM docker.io/library/maven:3.9.9-eclipse-temurin-21@sha256:3a4ab3276a087bf276f79cae96b1af04f53731bec53fb2e651aca79e4b10211e AS maven-build
+FROM docker.io/library/maven:3.9.12-eclipse-temurin-21@sha256:c3c9d3ac4ce8431a3995c0318b8d390f448e693dd4fabc16e9b68d2e1f3d7b46 AS maven-build
 
 WORKDIR /app