docs: update broken links in CONTRIBUTING.md #4323

Job	Run time
Generate SDKs	1m 19s
Run end-to-end tests (postgres)	41m 28s
Run end-to-end tests (cockroach)	44m 49s
Run tests and lints	19m 49s
Run Playwright end-to-end tests (postgres)	5m 27s
Run end-to-end tests (sqlite)	41m 34s
Run end-to-end tests (mysql)	42m 10s
Run Playwright end-to-end tests (cockroach)	5m 7s
Run Playwright end-to-end tests (sqlite)	5m 12s
Run Playwright end-to-end tests (mysql)	5m 2s
Build CLI docs	1m 9s
Generate changelog	0s
Generate release	0s
Draft newsletter	0s
Render version schema	0s
Release SDKs	0s
Pending approval Slack notification	0s
Send newsletter	0s
	3h 33m 6s

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