Eliminate deprecated CBOR formats #2126

Job	Run time
maybe-expedite	4s
lint	3m 52s
test (third-party, bincode, stable, false)	27m 16s
test (third-party, bincode, stable, true)	25m 21s
test (third-party, bincode, nightly, false)	29m 7s
test (third-party, bincode, nightly, true)	29m 25s
test (third-party, postcard, stable, false)	25m 50s
test (third-party, postcard, stable, true)	26m 45s
test (third-party, postcard, nightly, false)	28m 5s
test (third-party, postcard, nightly, true)	27m 56s
test (other, bincode, stable, false)	23m 17s
test (other, bincode, stable, true)	25m 32s
test (other, bincode, nightly, false)	29m 45s
test (other, bincode, nightly, true)	29m 27s
test (other, postcard, stable, false)	26m 6s
test (other, postcard, stable, true)	28m 21s
test (other, postcard, nightly, false)	32m 1s
test (other, postcard, nightly, true)	30m 19s
all-checks	1s
	7h 28m 30s

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