chore: remove duplicate entry for construct library graduation

duplicated by RFC #107 is in this table which is classified as `done`

README.md

@@ -44,7 +44,6 @@ future state of the libraries and to discover projects for contribution.
 [24](https://github.com/aws/aws-cdk-rfcs/issues/24)|[Resource imports](https://github.com/aws/aws-cdk-rfcs/issues/24)||💡 proposed
 [26](https://github.com/aws/aws-cdk-rfcs/issues/26)|[Monitoring packs](https://github.com/aws/aws-cdk-rfcs/issues/26)||💡 proposed
 [27](https://github.com/aws/aws-cdk-rfcs/issues/27)|[200 resource limit tools & guidance](https://github.com/aws/aws-cdk-rfcs/issues/27)||💡 proposed
-[28](https://github.com/aws/aws-cdk-rfcs/issues/28)|[Construct library graduation process](https://github.com/aws/aws-cdk-rfcs/issues/28)||💡 proposed
 [30](https://github.com/aws/aws-cdk-rfcs/issues/30)|[Improve synthesized template output](https://github.com/aws/aws-cdk-rfcs/issues/30)||💡 proposed
 [31](https://github.com/aws/aws-cdk-rfcs/issues/31)|[Integration tests](https://github.com/aws/aws-cdk-rfcs/issues/31)||💡 proposed
 [32](https://github.com/aws/aws-cdk-rfcs/issues/32)|[App-centric operational experience](https://github.com/aws/aws-cdk-rfcs/issues/32)||💡 proposed