[FLINK-35383][docs] Update compatibility matrix for 1.19 release

[z3d1k]

What is the purpose of the change

This pull requests updates the snapshot compatibility matrix for release 1.19.

Brief change log

Update compatibility matrix to include Flink 1.19 release

Verifying this change

This is a doc-only change.

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
• If yes, how is the feature documented? not applicable

[hlteoh37]

LGTM, thanks @z3d1k

[flinkbot]

CI report:

• b886507 Azure: SUCCESS

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