fix broken link to release_notes in readme
fix broken link to release_notes in readme

fable-compiler/Fable,fable-compiler/Fable,ncave/Fable,fable-compiler/Fable,fable-compiler/Fable,ncave/Fable,ncave/Fable,ncave/Fable,ncave/Fable,ncave/Fable,inosik/Fable,ncave/Fable,fable-compiler/Fable,inosik/Fable,fable-compiler/Fable,fable-compiler/Fable