Update base64 requirement from 0.13.0 to 0.21.3 #29505

Job	Run time
build (windows-latest)	2m 32s
build (ubuntu-latest)	2m 30s
build (macos-latest)	2m 44s
ci	2m 51s
check-bevy-internal-imports	8s
check-doc	14m 5s
check-missing-examples-in-docs	44s
miri	7m 49s
run-examples-on-windows-dx12	22m 21s
check-missing-features-in-docs	54s
markdownlint	1m 52s
build-wasm	0s
msrv	0s
check-compiles	0s
	58m 30s

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