MINOR: [Dev] Add Ben Harkins to collaborators

[pitrou]

This should allow assigning issues, if I read https://cwiki.apache.org/confluence/display/INFRA/Git+-+.asf.yaml+features correctly.

[pitrou]

cc @benibus

[ursabot]

Benchmark runs are scheduled for baseline = 345f5e1 and contender = 2e9f671. 2e9f671 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 ⬇️1.11% ⬆️0.0%] test-mac-arm
[Finished ⬇️0.77% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️1.93% ⬆️0.12%] ursa-thinkcentre-m75q
Buildkite builds:
[Finished] 2e9f671b ec2-t3-xlarge-us-east-2
[Failed] 2e9f671b test-mac-arm
[Finished] 2e9f671b ursa-i9-9960x
[Finished] 2e9f671b ursa-thinkcentre-m75q
[Finished] 345f5e18 ec2-t3-xlarge-us-east-2
[Finished] 345f5e18 test-mac-arm
[Finished] 345f5e18 ursa-i9-9960x
[Finished] 345f5e18 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