*: rename repo from pingcap/ticdc to pingcap/tiflow

[amyangfei]

What problem does this PR solve?

Finish step-6 in #3749 for release-5.1

What is changed and how it works?

• Run the following script

sed -i "s/github.com\/pingcap\/ticdc/github.com\/pingcap\/tiflow/g" $(find . -type f|grep -vE "bin/|.git")
sed -i "s/pingcap\/ticdc/pingcap\/tiflow/g" $(find . -type f|grep -vE "bin/|.git")
make fmt

• Change project name from ticdc to tiflow in Makefile

Check List

Tests

• Unit test
• Integration test

Release note

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• lance6716
• lonng

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[amyangfei]

/run-all-tests

[amyangfei]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: b62447d

[amyangfei]

/run-integration-test