Bump the minimum supported Go version to 1.20

[tagatac]

What is changing:

• Bump the Go version to 1.20
• Use that specific version in the GH action tests

Why this change is being made: jessevdk/go-flags requires Go 1.20: https://github.com/jessevdk/go-flags/blob/c02e333e441eb1187c25e6d689d769d499ec2a0b/go.mod#L3

Related issue(s): None

Follow-up changes needed: None

Is the change completely covered by unit tests? If not, why not?: N/A

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 93.28%. Comparing base (2ec2203) to head (7aa570e). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #65 +/- ## ======================================= Coverage 93.28% 93.28% ======================================= Files 14 14 Lines 789 789 ======================================= Hits 736 736 Misses 49 49 Partials 4 4 ```

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