feat(postgres): native upsert

[sushantdhiman]

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Description of change

Closes #11246
Fixes #4132
Fixes #12051
Fixes #9629
Fixes #9216

[codecov]

Codecov Report

Merging #12301 into master will decrease coverage by 0.04%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master   #12301      +/-   ##
==========================================
- Coverage   96.34%   96.29%   -0.05%     
==========================================
  Files          95       95              
  Lines        9127     9127              
==========================================
- Hits         8793     8789       -4     
- Misses        334      338       +4     

Impacted Files	Coverage Δ
lib/dialects/abstract/index.js	100.00% <ø> (ø)
lib/dialects/mysql/query-generator.js	97.56% <ø> (-0.06%)	⬇️
lib/dialects/postgres/query-generator.js	92.46% <ø> (-2.19%)	⬇️
lib/dialects/postgres/query-interface.js	98.92% <ø> (-0.02%)	⬇️
lib/dialects/sqlite/query-generator.js	96.50% <ø> (-0.14%)	⬇️
lib/dialects/abstract/query-generator.js	97.39% <100.00%> (+0.25%)	⬆️
lib/dialects/abstract/query-interface.js	93.76% <100.00%> (+0.17%)	⬆️
lib/dialects/mariadb/query.js	87.96% <100.00%> (+0.18%)	⬆️
lib/dialects/mssql/query-interface.js	100.00% <100.00%> (ø)
lib/dialects/mssql/query.js	94.62% <100.00%> (ø)
... and 6 more

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[SimonSchick]

Can't say much about the query logic changes, I'm not really a postgres user, some comments on the code though.

[papb]

Does this work for all 5 dialects now?

[sushantdhiman]

Except for mariadb, which does not support RETURINING * at all, in current 10.1 target version. But it wont fail

[papb]

I am confused, if it is not supported by MariaDB, then why could the following code be removed:

    if (options.returning === true && primaryKey) {
      const record = await this.findByPk(primaryKey, options);
      result = [record, created];

[sushantdhiman]

This works but it is buggy, see linked issues. Plus one extra read from database. So I decided to not support this for mariadb.

[sushantdhiman]

@papb I think I have taken care of all points raised by you, I am merging this PR. Let me know if you have any questions