[RCD-37] ChangeLog: address PR entries assigned to me
[RCD-37] ChangeLog: address PR entries assigned to me

input-output-hk/cardano-sl,input-output-hk/cardano-sl,input-output-hk/pos-haskell-prototype,input-output-hk/pos-haskell-prototype,input-output-hk/cardano-sl,input-output-hk/pos-haskell-prototype,input-output-hk/cardano-sl