Bump minimum dbt-adapters requirement to 1.9.0

[QMalcolm]

Resolves #10996

Problem

In dbt-core we've made a switch from an environment variable for gating microbatch functionality to a project flag (#10799). In dbt-adapters we've done likewise (dbt-labs/dbt-adapters#323). For everything to work properly, we need depend on those changes in dbt-adapters, which will go out in 1.12.0

Solution

bump dbt-core's requirement spec for dbt-adapters to have a minimum of 1.12.0

Checklist

• I have read the contributing guide and understand what's expected of me.
• I have run this code in development, and it appears to resolve the stated issue.
• This PR includes tests, or tests are not required or relevant for this PR.
• This PR has no interface changes (e.g., macros, CLI, logs, JSON artifacts, config files, adapter interface, etc.) or this PR has already received feedback and approval from Product or DX.
• This PR includes type annotations for new and modified functions.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.07%. Comparing base (e9a2b54) to head (a574383).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10998      +/-   ##
==========================================
+ Coverage   89.05%   89.07%   +0.01%     
==========================================
  Files         183      183              
  Lines       23626    23626              
==========================================
+ Hits        21040    21044       +4     
+ Misses       2586     2582       -4     

Flag	Coverage Δ
integration	86.37% <ø> (+0.01%)	⬆️
unit	62.79% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
Unit Tests	62.79% <ø> (ø)
Integration Tests	86.37% <ø> (+0.01%)	⬆️

[QMalcolm]

Tests won't pass until we do the dbt-adapters release