ARROW-16301: [C#][CI] Fix docker configuration for .NET 6

[kszucs]

No description provided.

[kszucs]

@github-actions crossbow submit nuget

[github-actions]

https://issues.apache.org/jira/browse/ARROW-16301

[github-actions]

⚠️ Ticket has not been started in JIRA, please click 'Start Progress'.

[github-actions]

Revision: 63d3ece

Submitted crossbow builds: ursacomputing/crossbow @ actions-1938

Task	Status
nuget

[kou]

+1

[ursabot]

Benchmark runs are scheduled for baseline = 95c8984 and contender = 4a26683. 4a26683 is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Finished ⬇️0.0% ⬆️0.0%] ec2-t3-xlarge-us-east-2
[Failed] test-mac-arm
[Failed ⬇️0.0% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️0.29% ⬆️0.0%] ursa-thinkcentre-m75q
Buildkite builds:
[Finished] 4a266834 ec2-t3-xlarge-us-east-2
[Failed] 4a266834 test-mac-arm
[Failed] 4a266834 ursa-i9-9960x
[Finished] 4a266834 ursa-thinkcentre-m75q
[Finished] 95c8984f ec2-t3-xlarge-us-east-2
[Failed] 95c8984f test-mac-arm
[Finished] 95c8984f ursa-i9-9960x
[Finished] 95c8984f ursa-thinkcentre-m75q
Supported benchmarks:
ec2-t3-xlarge-us-east-2: Supported benchmark langs: Python, R. Runs only benchmarks with cloud = True
test-mac-arm: Supported benchmark langs: C++, Python, R
ursa-i9-9960x: Supported benchmark langs: Python, R, JavaScript
ursa-thinkcentre-m75q: Supported benchmark langs: C++, Java