fluid this pr is to fix a wrong time of Copyright

Ⅰ. Describe what this PR does

this pr is to fix a wrong time of Copyright from 2023 to 2020 in the file"pkg/ddc/alluxio/types.go",so the Task 166 is finished.

Ⅱ. Does this pull request fix one issue?

fixes #XXXX

Ⅲ. List the added test cases (unit test/integration test) if any, please explain if no tests are needed.

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

May 06 '24 15:05 VictorChen77

Hi @VictorChen77. Thanks for your PR.

I'm waiting for a fluid-cloudnative member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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