Fix version specification for redshift-connector

[asnare]

Changes

This PR fixes the version specification for the redshift-connector dependency, introduced in #2305: as written it allows for higher 2.x versions (e.g. 2.2) as well as downgrades to earlier versions of the connector (e.g. 2.1.7) that were not used during development or tested.

Relevant implementation details

When using ~= with semantic versioning, the complete minimum version needs to be specified.

Linked issues

Noticed when reviewing #2466, which downgrades redshift-connector to escape a version constraint on lxml. Coincidentally includes #2464.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 65.05%. Comparing base (dc60917) to head (81df21e).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2467   +/-   ##
=======================================
  Coverage   65.05%   65.05%           
=======================================
  Files         107      107           
  Lines        9524     9524           
  Branches     1008     1008           
=======================================
  Hits         6196     6196           
  Misses       3149     3149           
  Partials      179      179           

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[github-actions]

✅ 157/157 passed, 6 flaky, 3 skipped, 44m2s total

Flaky tests:

• 🤪 test_installs_and_runs_local_bladebridge (12.864s)
• 🤪 test_installs_and_runs_pypi_bladebridge (23.482s)
• 🤪 test_transpiles_informatica_to_sparksql_non_interactive[False] (25.993s)
• 🤪 test_transpile_teradata_sql_non_interactive[True] (28.435s)
• 🤪 test_transpile_teradata_sql (32.455s)
• 🤪 test_transpile_teradata_sql_non_interactive[False] (26.483s)

_{Running from acceptance #4549}