Bump mysql2 from 3.9.8 to 3.15.1 #479

Job	Run time
Validation	9s
Git linter (Lintje)	10s
Ruby linter (RuboCop)	15s
JavaScript linter (Prettier)	56s
Node.js 22 - Build	57s
Node.js 18 - Build	57s
Node.js 20 - Build	55s
Node.js 23 - Build	55s
Integration tests (Express + Postgres)	2m 6s
Integration tests (Express + Knex.js)	2m 4s
Integration tests (Express + Prisma + Postgres)	2m 3s
Integration tests (Koa + Mongo)	1m 59s
Integration tests (Express + Redis)	2m 48s
Integration tests (Express + Yoga)	1m 52s
Integration tests (Fastify)	1m 54s
Integration tests (Next.js)	2m 7s
Integration tests (Koa + MySQL)	2m 35s
Integration tests (Nest.js)	2m 6s
Integration tests (Express + Prisma + Mongo)	2m 19s
Integration tests (Express + Apollo)	1m 52s
Integration tests (Express + Mongoose)	2m 4s
Node.js 20 - Extra test - diagnose	3m 12s
Node.js 20 - Tests	1m 31s
Node.js 23 - Extra test - diagnose	2m 53s
Node.js 23 - Tests	57s
Node.js 18 - Tests	1m 17s
Node.js 18 - Extra test - diagnose	3m 55s
Node.js 22 - Extra test - diagnose	3m 2s
Node.js 22 - Tests	1m 24s
Node.js 23 - Clean up	0s
Node.js 22 - Clean up	0s
Node.js 20 - Clean up	0s
Node.js 18 - Clean up	-1s
	51m 13s

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