[FLINK-37533][CI] Reduce the stale PR github action timeouts

[tomncooper]

FLINK-37026 enabled the Stale PR GitHub Action and this has been running successfully for several months, labelling PRs older than 6 months as "stale".

The initial time-outs for the Stale PR action were 6 months inactive with 3 further months of no action before closing. This was done to give time for PR authors to react to the new action. However, during the discussion it was suggested that 3 months inactive with 1 month to respond was the typical configuration used on other Apache projects and should also be used for Flink. It was decided to start with longer time-outs and move to the standard ones once the stability of the action was confirmed.

Now that the action has been running for some time with no issues, we should reduce the time-outs to the proposed Apache standard configuration (90 days inactive with 30 to respond). This will allow us to start clearing the oldest stale PRs.

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

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): no
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: no
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? no

[flinkbot]

CI report:

• 8374d7a Azure: SUCCESS

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[rmetzger]

Thanks, this looks good and in line with the community decision.