Reexport snforge_scarb_plugin (#3000)

<!-- Reference any GitHub issues resolved by this PR -->

Closes #2999

## Introduced changes

<!-- A brief description of the changes -->

- Reexported `snforge_scarb_plugin` based on
https://github.com/software-mansion/scarb/pull/2000/files#diff-9027147cd5fb117cc5d9d5c85f24128c489f5d48ea8dd17e5f67991a88fc6e4c

## Checklist

<!-- Make sure all of these are complete -->

- [x] Linked relevant issue
- [x] Updated relevant documentation
- [x] Added relevant tests
- [x] Performed self-review of the code
- [x] Added changes to `CHANGELOG.md`

Author: cptartur

snforge_std/Scarb.toml

@@ -6,6 +6,7 @@ description = "Cairo testing library"
 documentation = "https://foundry-rs.github.io/starknet-foundry/appendix/snforge-library.html"
 repository = "https://github.com/foundry-rs/starknet-foundry"
 license-file = "../LICENSE"
+re-export-cairo-plugins = ["snforge_scarb_plugin"]
 
 [dependencies]
 snforge_scarb_plugin = { path = "../crates/snforge-scarb-plugin" }