[FLINK-32392][ci] Invalidate Maven repo cache on Azure every year to reduce its disk usage

[PatrickRen]

What is the purpose of the change

This pull request adds year number before the cache key of local Maven repo on Azure Pipeline, so that the cache will be invalidated per year, in order to reduce the disk usage of Maven repo.

Brief change log

• Invalidate Maven repo cache on Azure every year to reduce its disk usage

Verifying this change

This change is already covered by existing tests.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (yes / no)
• The serializers: (yes / no / don't know)
• The runtime per-record code paths (performance sensitive): (yes / no / don't know)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: (yes / no / don't know)
• The S3 file system connector: (yes / no / don't know)

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)

[flinkbot]

CI report:

• 7895ce3 Azure: SUCCESS

Bot commands

The @flinkbot bot supports the following commands:

• @flinkbot run azure re-run the last Azure build

[PatrickRen]

@rmetzger could you take a look at this PR? Thanks!

[rmetzger]

When I first saw the change, I was worried that we might get an outage on January 1st because re-downloading all the mvn artifacts has high failure rates. But I see your CI run has passed, so I'm more optimistic.