MAINT: Remove reference to old 2.0.0 branch (#2482) #4380

Job	Run time
Check code style issues	40s
pytest on windows	4m 48s
Build & verify package	21s
pytest on 3.7 (crypto-lib: cryptography)	3m 48s
pytest on 3.8 (crypto-lib: cryptography)	3m 35s
pytest on 3.9 (crypto-lib: cryptography)	3m 47s
pytest on 3.10 (crypto-lib: cryptography)	3m 35s
pytest on 3.11 (crypto-lib: cryptography)	3m 24s
pytest on 3.12 (crypto-lib: cryptography)	4m 49s
pytest on 3.7 (crypto-lib: pycryptodome)	3m 35s
pytest on 3.7 (crypto-lib: none)	3m 53s
Combine & check coverage.	16s
	36m 31s

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