fix(associations): allow binary key for belongs-to-many

[tsasaki609]

Pull Request check-list

Please make sure to review and check all of these items:

• Does npm run test or npm run test-DIALECT pass with this change (including linting)?
• Does the description below contain a link to an existing issue (Closes #[issue]) or a description of the issue you are solving?
• Have you added new tests to prevent regressions?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?
• Did you update the typescript typings accordingly (if applicable)?
• Did you follow the commit message conventions explained in CONTRIBUTING.md?

Description of change

fix #11545

[tsasaki609]

Oops CI failed...

SequelizeDatabaseError: BLOB/TEXT column 'id' used in key specification without a key length

MySQL requires a length specification for the BLOB data type.
I'll try to fix.

[codecov]

Codecov Report

Merging #11578 into master will decrease coverage by 0.4%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #11578      +/-   ##
==========================================
- Coverage   96.27%   95.87%   -0.41%     
==========================================
  Files          94       91       -3     
  Lines        9186     8984     -202     
==========================================
- Hits         8844     8613     -231     
- Misses        342      371      +29

Impacted Files	Coverage Δ
lib/associations/belongs-to-many.js	98.07% <100%> (ø)	⬆️
lib/dialects/mariadb/query-generator.js	14.28% <0%> (-85.72%)	⬇️
lib/dialects/mariadb/data-types.js	50.98% <0%> (-49.02%)	⬇️
lib/query-interface.js	90.73% <0%> (-1.47%)	⬇️
lib/sequelize.js	95.32% <0%> (-0.63%)	⬇️
lib/dialects/mariadb/index.js
lib/dialects/mariadb/connection-manager.js
lib/dialects/mariadb/query.js

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 2b9baa2...73b9363. Read the comment docs.

[sushantdhiman]

@tsasaki609 merged to master which is currently pointing to v6-beta, if you need a v5 release please submit a new PR for v5 branch as well