fix: readme and core-sdk before summer

[zFernand0]

What It Does

Suppress annoying config-file missing warnings

How to Test

Run a script and notice that the config_file missing warnings don't show up

Review Checklist
I certify that I have:

• tested my changes
• added/updated automated tests
• updated the changelog
• followed the contribution guidelines

Additional Comments

[codecov]

Codecov Report

Attention: Patch coverage is 66.66667% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 84.84%. Comparing base (d388ac4) to head (bb4633c).
Report is 2 commits behind head on main.

Files	Patch %	Lines
src/core/zowe/core_for_zowe_sdk/config_file.py	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #263      +/-   ##
==========================================
- Coverage   84.88%   84.84%   -0.04%     
==========================================
  Files          34       34              
  Lines        2124     2125       +1     
==========================================
  Hits         1803     1803              
- Misses        321      322       +1     

Flag	Coverage Δ
unittests	84.84% <66.66%> (-0.04%)	⬇️

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