[FLINK-37812][doc] Fix broken links to Apache Avro in doc and code

[liuml07]

What is the purpose of the change

Recently Apache Avro changed the documentation website. Lovely as it is, some links are broken linked from Apache Flink documentation and comments in code. Let's simply fix them by updating to new working links.

Brief change log

• Find all existing links by rg 'https://avro.apache.org/docs/'
• Replace with new link prefix https://avro.apache.org/docs/++version++/
• Update the page-specific link etc

Verifying this change

Manually checked those links are valid in the change.

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)

[liuml07]

This PR refers to the latest version of Avro instead of each minor version in all places (see below). Note the version-specific link is not working currently: https://avro.apache.org/docs/1.11.4/api/java/index.html Also it gets stale if we put version specific links when we upgrade Avro version in pom.xml.

[davidradl]

I have raised https://issues.apache.org/jira/browse/AVRO-4141 to get the Avro docs fixed - as all the api links for each language are broken for 1.11.4. It was closed as duplicate https://issues.apache.org/jira/browse/AVRO-4128. I have asked for the priority to be raised from minor, as there is no documented API for Avro at this release!

[liuml07]

Thanks David!

As most places in the Flink doc, in this PR we link all places to the latest version instead of minor versions. That assumes we do not have big lag in adopting the Apache Avro versions, and users can always find version-specific doc in Avro doc page.

[flinkbot]

CI report:

• be8bfed Azure: SUCCESS

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