deps: update docker.io/library/maven:3.9.9-eclipse-temurin-11-alpine docker digest to 9a259c6 (#3554)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| docker.io/library/maven | stage | digest | `3bab9f2` -> `9a259c6` |

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Co-authored-by: Diego Marquez <[email protected]>

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.cloudbuild/library_generation/library_generation.Dockerfile

@@ -15,7 +15,7 @@
 # install gapic-generator-java in a separate layer so we don't overload the image
 # with the transferred source code and jars
 
-FROM docker.io/library/maven:3.9.9-eclipse-temurin-11-alpine@sha256:3bab9f2cd4fa8704445bf01444e8e5e0f1ab819a41616069872a898b432a7309 AS ggj-build
+FROM docker.io/library/maven:3.9.9-eclipse-temurin-11-alpine@sha256:9a259c69e57564f1d13f6f5b275e37c638c3103dc1978237e90b6d4d66bc9b0c AS ggj-build
 
 WORKDIR /sdk-platform-java
 COPY . .