Bump product_version to 1.0.1 and align backport targets

[Jan-Kazlouski-elastic]

Closes #482

After releasing 1.0.0, main still had product_version 1.0.0, so Docker publishes from main continued to overwrite 1.0.0-SNAPSHOT. That conflates the released image with the next development snapshot.

Changes

• Bump product_version on main to 1.0.1 so the next publish from main produces docker.elastic.co/integrations/crawler:1.0.1-SNAPSHOT
• Update .backportrc.json backport targets to the supported lines only: main and 1.0 (drop stale 0.4 / 0.3 / 0.2 and the obsolete v0.5.0 → main mapping)

Checklists

Pre-Review Checklist

• This PR does NOT contain credentials of any kind, such as API keys or username/passwords (double check crawler.yml.example and elasticsearch.yml.example)
• This PR has a meaningful title
• This PR links to all relevant GitHub issues that it fixes or partially addresses
• this PR has a thorough description
• Covered the changes with automated tests
• Tested the changes locally
• Added a label for each target release version (example: v0.1.0)
• Considered corresponding documentation changes
• Contributed any configuration settings changes to the configuration reference
• Ran make notice if any dependencies have been added

Changes Requiring Extra Attention

None. Version metadata and backport config only.

Related Pull Requests

N/A

Release Note

None. Internal versioning / release-process hygiene.

[github-actions]

💔 Failed to create backport PR(s)

Status	Branch	Result
❌	1.0	Commit could not be cherrypicked due to conflicts

To backport manually run:
backport --pr 483 --autoMerge --autoMergeMethod squash