Add RELEASE_PROCESS note about manually updating the Playground
Add RELEASE_PROCESS note about manually updating the Playground

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cquinn/ponyc,sgebbie/ponyc,jemc/ponyc,sgebbie/ponyc,jemc/ponyc,ponylang/ponyc,kulibali/ponyc,sgebbie/ponyc,dipinhora/ponyc,sgebbie/ponyc,kulibali/ponyc,cquinn/ponyc,ponylang/ponyc,dipinhora/ponyc,ponylang/ponyc,sgebbie/ponyc,cquinn/ponyc,kulibali/ponyc,cquinn/ponyc,kulibali/ponyc,jemc/ponyc,dipinhora/ponyc