docs: Update custom extractor Poetry instructions

[EMCP]

the build and publish command have been changed in poetry

[netlify]

👷 Deploy request for meltano pending review.

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Name	Link
🔨 Latest commit	fe5d68d

[EMCP]

@afolson , thanks for the quick response.. hope this format works otherwise I can use the multi line ```bash approach

like
so

[afolson]

@edgarrmondragon Is this the best way to do this now? Looks like --build was deprecated a bit ago.

[codecov]

Codecov Report

Merging #7035 (1df3232) into main (e319251) will decrease coverage by 0.01%.
The diff coverage is n/a.

❗ Current head 1df3232 differs from pull request most recent head fe5d68d. Consider uploading reports for the commit fe5d68d to get more accurate results

@@            Coverage Diff             @@
##             main    #7035      +/-   ##
==========================================
- Coverage   88.65%   88.63%   -0.02%     
==========================================
  Files         292      292              
  Lines       21318    21318              
  Branches     2106     2106              
==========================================
- Hits        18899    18896       -3     
- Misses       2061     2063       +2     
- Partials      358      359       +1     

Impacted Files	Coverage Δ
src/meltano/cli/elt.py	93.85% <0.00%> (-1.12%)	⬇️
src/meltano/core/elt_context.py	95.86% <0.00%> (-0.69%)	⬇️

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[edgarrmondragon]

@edgarrmondragon Is this the best way to do this now? Looks like --build was deprecated a bit ago.

@afolson yup, the official docs now use commands build and publish

[edgarrmondragon]

Thanks @EMCP!