Upgrade botan to 0.11 #1689

Job	Run time
Check semver compatibility	3m 16s
Build rustls-cert-gen as a standalone package	24s
build-windows	14m 10s
build (macOS-latest, stable)	4m 42s
Validate external types appearing in public API	1m 43s
build (ubuntu-latest, stable)	7m 1s
Measure coverage	6m 55s
build (ubuntu-latest, beta)	7m 3s
Format & clippy	6m 21s
build (ubuntu-latest, nightly)	6m 52s
Documentation (stable)	1m 5s
build (ubuntu-latest, stable 7 months ago)	7m 6s
Documentation (nightly)	1m 14s
	1h 7m 52s

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