docs: Expand v3 upgrade guide to cover all breaking changes #372

Job	Run time
PR title check	5s
Code checks / Actions lint check	28s
Code checks / Spell check	5s
Tests / Integration tests (3.14, ubuntu-latest)	2m 16s
Docstrings checks / Docstrings checks	14s
Tests / Integration tests (3.11, ubuntu-latest)	2m 13s
Doc checks / Doc checks / Docs check	1m 13s
Code checks / Lint check / Lint check (3.14)	15s
Code checks / Lint check / Lint check (3.13)	10s
Code checks / Type check / Type check (3.13)	11s
Code checks / Lint check / Lint check (3.12)	10s
Code checks / Type check / Type check (3.11)	9s
Code checks / Lint check / Lint check (3.11)	8s
Code checks / Type check / Type check (3.12)	13s
Code checks / Type check / Type check (3.14)	16s
Tests / Unit tests / Unit tests (ubuntu-latest, 3.13)	38s
Tests / Unit tests / Unit tests (ubuntu-latest, 3.14)	34s
Tests / Unit tests / Unit tests (windows-latest, 3.13)	57s
Tests / Unit tests / Unit tests (ubuntu-latest, 3.11)	37s
Tests / Unit tests / Unit tests (windows-latest, 3.14)	58s
Tests / Unit tests / Unit tests (windows-latest, 3.11)	1m 0s
Tests / Unit tests / Unit tests (windows-latest, 3.12)	1m 2s
Tests / Unit tests / Unit tests (ubuntu-latest, 3.12)	43s
	14m 35s

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