ci: Migrate CircleCI automation to github actions.

[winder]

Summary

Migrate CircleCI automation to github actions.

Test Plan

Verify that this PR trigger the new automation, and the automation runs correctly.

[codecov]

Codecov Report

Merging #62 (3f891af) into master (442791a) will increase coverage by 1.74%.
The diff coverage is 71.27%.

@@            Coverage Diff             @@
##           master      #62      +/-   ##
==========================================
+ Coverage   67.66%   69.40%   +1.74%     
==========================================
  Files          32       33       +1     
  Lines        1976     2056      +80     
==========================================
+ Hits         1337     1427      +90     
+ Misses        570      554      -16     
- Partials       69       75       +6     

Impacted Files	Coverage Δ
conduit/data/block_export_data.go	100.00% <ø> (+92.30%)	⬆️
conduit/plugins/importers/algod/metrics.go	100.00% <ø> (ø)
...lugins/exporters/postgresql/postgresql_exporter.go	66.66% <51.21%> (-11.54%)	⬇️
conduit/pipeline/pipeline.go	66.09% <72.10%> (+0.64%)	⬆️
conduit/data/config.go	76.47% <76.47%> (ø)
conduit/plugins/importers/algod/algod_importer.go	88.36% <76.47%> (+0.05%)	⬆️
conduit/pipeline/errors.go	100.00% <100.00%> (ø)

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[winder]

I'll need to update the project's CI requirements after this is merged.

[tzaffi]

Dropping the nightly tests?

Seems like they were identical to the on-commit tests (if they were even being run) so it's fine by me. If in the future we need to revive them, we can.

[winder]

They weren't being run.

The difference compared to the on-commit tests are:

- CHANNEL=stable
+ CHANNEL=nightly

and maybe:

- FILENAME="fa6ad40d/rel-nightly
+ FILENAME="rel-nightly"

I tried to make the workflow parameterized in this PR but it wasn't working. Agreed about bringing them back in the future. This is the same problem we have in SDKs: what version of algod should we be testing against?

[winder]

cc: @cce we've talked about this before, you might be curious. This is one way we pin versions between repositories. It means there is a gap where we don't know if the downstream tools are still compatible with algod.

[tzaffi]

LGTM