fix(sdk): update kfp-server-api dependencies and bump sdk version to 2.0.0-alpha.1

[chensun]

Description of your changes:
Fixing error

ERROR: Cannot install kfp-server-api 2.0.0a0 (from /python_http_client) and kfp==2.0.0a0 because these package versions have conflicting dependencies.
The conflict is caused by:
    The user requested kfp-server-api 2.0.0a0 (from /python_http_client)
    kfp 2.0.0a0 depends on kfp-server-api<2.0.0 and >=1.1.2

Checklist:

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[connor-mccarthy]

Thank you, Chen.

/lgtm
/approve

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: connor-mccarthy

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[chensun]

/test kubeflow-pipelines-samples-v2

[chensun]

/hold

[chensun]

/unhold