This means that updating hledger-lib will automatically force us to
update hledger-check-fancyassertions. Any new hash mismatch will be
caught by src.name changing, forcing a rebuild of the derivation.
haskellPackages.hledger-lib_1_24_1: init at 1.24.1
haskellPackages.hledger_1_24: remove at 1.24
haskellPackages.hledger-lib_1_24: remove at 1.24
hledger-check-fancyassertions: build using hledger-lib 1.24.1