Add PKCS#10 attributes to CSR serializer #1622

Job	Run time
Validate external types appearing in public API	1m 37s
Documentation (stable)	1m 5s
Documentation (nightly)	1m 3s
build (macOS-latest, stable)	3m 26s
Build rustls-cert-gen as a standalone package	31s
build (ubuntu-latest, stable)	5m 37s
build-windows	10m 22s
build (ubuntu-latest, beta)	5m 48s
Measure coverage	5m 55s
build (ubuntu-latest, nightly)	5m 33s
Format & clippy	5m 29s
Check semver compatibility	59s
build (ubuntu-latest, stable 7 months ago)	5m 45s
	53m 10s

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