feat(tiflow): update base image to use rockylinux8

[purelind]

CentOS 7 has reached the end of its life cycle. Starting from version 8.4, we began using Rocky Linux 8 as the base image.

[ti-chi-bot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[purelind]

retest link

• pull_verify https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftiflow%2Fghpr_verify/detail/ghpr_verify/2801/pipeline
• pull_engine_integration_test

1. https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftiflow%2Fpull_engine_integration_test/detail/pull_engine_integration_test/2645/pipeline
2. https://do.pingcap.net/jenkins/job/pingcap/job/tiflow/job/pull_engine_integration_test/2648/

• pull_dm_compatibility_test

1. https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftiflow%2Fpull_dm_compatibility_test/detail/pull_dm_compatibility_test/2868/pipeline
2. https://do.pingcap.net/jenkins/job/pingcap/job/tiflow/job/pull_dm_compatibility_test/2876/
3. https://do.pingcap.net/jenkins/job/pingcap/job/tiflow/job/pull_dm_compatibility_test/2882/

• pull_dm_integration_test

1. https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftiflow%2Fpull_dm_integration_test/detail/pull_dm_integration_test/3060/pipeline
2. https://do.pingcap.net/jenkins/job/pingcap/job/tiflow/job/pull_dm_integration_test/3070/

• pull_cdc_integration_storage_test

1. https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftiflow%2Fpull_cdc_integration_storage_test/detail/pull_cdc_integration_storage_test/2833/pipeline
2. https://do.pingcap.net/jenkins/job/pingcap/job/tiflow/job/pull_cdc_integration_storage_test/2835/
3. https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftiflow%2Fpull_cdc_integration_storage_test/detail/pull_cdc_integration_storage_test/2842/pipeline

• pull_cdc_integration_pulsar_test

1. https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftiflow%2Fpull_cdc_integration_pulsar_test/detail/pull_cdc_integration_pulsar_test/2564/
2. https://do.pingcap.net/jenkins/job/pingcap/job/tiflow/job/pull_cdc_integration_pulsar_test/2566/
3. https://do.pingcap.net/jenkins/job/pingcap/job/tiflow/job/pull_cdc_integration_pulsar_test/2575/

• pull_cdc_integration_mysql_test

1. https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftiflow%2Fpull_cdc_integration_test/detail/pull_cdc_integration_test/2898/pipeline
2. https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftiflow%2Fpull_cdc_integration_test/detail/pull_cdc_integration_test/2908/pipeline

• pull_cdc_integration_kafka_test

1. https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftiflow%2Fpull_cdc_integration_kafka_test/detail/pull_cdc_integration_kafka_test/3026/pipeline
2. https://do.pingcap.net/jenkins/job/pingcap/job/tiflow/job/pull_cdc_integration_kafka_test/3028/