Add release notes for v0.4.8. #6924

Job	Run time
Pre-commit checks / Pre-commit Checks	50s
Check towncrier / Towncrier Checks	42s
Package Toga (core) / Create Python Package	15s
Package Toga (android) / Create Python Package	19s
Package Toga (cocoa) / Create Python Package	15s
Package Toga (demo) / Create Python Package	16s
Package Toga (dummy) / Create Python Package	14s
Package Toga (gtk) / Create Python Package	18s
Package Toga (iOS) / Create Python Package	19s
Package Toga (textual) / Create Python Package	21s
Package Toga (toga) / Create Python Package	18s
Package Toga (web) / Create Python Package	18s
Package Toga (winforms) / Create Python Package	26s
Test core (macos-latest, 3.9)	46s
Test core (macos-latest, 3.10)	43s
Test core (macos-latest, 3.11)	46s
Test core (macos-latest, 3.12)	47s
Test core (macos-latest, 3.13)	1m 3s
Test core (ubuntu-latest, 3.9)	51s
Test core (ubuntu-latest, 3.10)	47s
Test core (ubuntu-latest, 3.11)	52s
Test core (ubuntu-latest, 3.12)	1m 5s
Test core (ubuntu-latest, 3.13)	1m 11s
Test core (windows-latest, 3.9)	2m 18s
Test core (windows-latest, 3.10)	1m 37s
Test core (windows-latest, 3.11)	1m 41s
Test core (windows-latest, 3.12)	1m 35s
Test core (windows-latest, 3.13)	2m 25s
Coverage	34s
Testbed (macOS-x86_64)	4m 53s
Testbed (macOS-arm64)	3m 31s
Testbed (windows)	5m 6s
Testbed (linux-x11)	3m 43s
Testbed (linux-wayland)	3m 54s
Testbed (android)	8m 27s
Testbed (iOS)	6m 26s
Testbed (textual-linux)	51s
Testbed (textual-macOS)	57s
Testbed (textual-windows)	1m 52s
	1h 3m 32s

Provide feedback