message: Add release notes describing blockmaxweight deprecation
  Github-Pull:
  Rebased-From:
diff: @@ -72,6 +72,22 @@ Notable changes
  value is passed, instead of returning a list of all wallet transactions since
  the genesis block.
  +Miner block size limiting deprecated
  +------------------------------------
  +
  +Though blockmaxweight has been preferred for limiting the size of blocks returned by
  +getblocktemplate since 0.13.0, blockmaxsize remained as an option for those who wished
  +to limit their block size directly. Using this option resulted in a few UI issues as
  +well as non-optimal fee selection and ever-so-slightly worse performance, and has thus
  +now been deprecated. Further, the blockmaxsize option is now used only to calculate an
  +implied blockmaxweight, instead of limiting block size directly. Any miners who wish
  +to limit their blocks by size, instead of by weight, will have to do so manually by
  +removing transactions from their block template directly.
  +
  +Low-level RPC changes
  +----------------------
  +- The "currentblocksize" value in getmininginfo has been removed.
  +
  Credits
  =======
  