Target .NET Framework 4.7.2

[qed-]

Rationale for this change

Target .Net Framewok 4.7.1 rather than 4.6.1 due to dependency on netstandard2.0

See #41347

[github-actions]

Thanks for opening a pull request!

If this is not a minor PR. Could you open an issue for this pull request on GitHub? https://github.com/apache/arrow/issues/new/choose

Opening GitHub issues ahead of time contributes to the Openness of the Apache Arrow project.

Then could you also rename the pull request title in the following format?

GH-${GITHUB_ISSUE_ID}: [${COMPONENT}] ${SUMMARY}

or

MINOR: [${COMPONENT}] ${SUMMARY}

In the case of PARQUET issues on JIRA the title also supports:

PARQUET-${JIRA_ISSUE_ID}: [${COMPONENT}] ${SUMMARY}

See also:

• Other pull requests
• Contribution Guidelines - Contributing Overview

[CurtHagenlocher]

We still want to support net462 in the core Arrow project because it's not yet at end-of-life. The change to net472 should be in Apache.Arrow.Flight.csproj.

[CurtHagenlocher]

@qed- , I've checked in the equivalent of this change now so I'm going to close this PR. If you feel this decision is in error, please feel free to reopen or resubmit.