fix: Propagate SIGINT to subprocess

[ReubenFrankel]

My knowledge of asyncio is quite limited but this seems to fix the issue for me. Please let me know if this can be optimised or there is more of a best-practice approach.

^CGracefully stopping... (press Ctrl+C again to force)
Aborting on container exit...
time="2023-03-03T01:12:55Z" level=error msg="got 3 SIGTERM/SIGINTs, forcing shutdown"
Container matatika-ext-app-1  Stopping
Container matatika-ext-app-1  Stopped
Container matatika-ext-catalog-1  Stopping
Container matatika-ext-catalog-1  Stopped
Container matatika-ext-db-1  Stopping
Container matatika-ext-db-1  Stopped
canceled


error invoking matatika None   error_message=Matatika invocation failed returncode=1

Could of unresolved minor issues:

• Not sure what the got 3 SIGTERM/SIGINTs, forcing shutdown message is about - this doesn't happen when I Ctrl+C a docker compose up process directly
• Usually the return code when you Ctrl+C a docker compose up process is 130, but here it is 1 (could be down to the above error)

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Checklist

• Implement fix to propagate SIGINT signal to asyncio subprocess
• Add test(s)

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Resolves #74

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📚 Documentation preview 📚: https://meltano-edk--75.org.readthedocs.build/en/75/

[WillDaSilva]

@ReubenFrankel Thanks you for this improvement. It looks good to me, but before we merge it in I'd appreciate the addition to a test to ensure it works, and to ensure there is no regression in this behaviour in the future.

[ReubenFrankel]

@WillDaSilva I would be happy to do that. Is there an example I can follow somewhere already in the Meltano codebase? Just spent a while trying to adapt a copy of test_exec to fire a SIGINT signal to the mocked process, but have had no luck so far...