Bump Cairo and Scarb to 2.3.0 (#955)

Did not verify the new sierra class hashes, but afaik we have a task to
automate those tests #929
Wrapping tests in src in `#[cfg(test)]` was needed - it shouldn't have
been allowed in the first place before, seems like a fixed compiler bug

## Introduced changes

Self-explanatory.

## Checklist

- [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`

.github/workflows/ci.yml

@@ -12,7 +12,7 @@ jobs:
   test-forge-unit-and-integration:
     name: Test Forge / Unit and Integration Tests
     env:
-      SCARB_VERSION: 0.7.0
+      SCARB_VERSION: 2.3.0
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
@@ -29,7 +29,7 @@ jobs:
   test-forge-e2e:
     name: Test Forge / E2E Tests
     env:
-      SCARB_VERSION: 0.7.0
+      SCARB_VERSION: 2.3.0
     runs-on: ubuntu-latest
     steps:
       - name: Extract branch name
@@ -67,7 +67,7 @@ jobs:
   test-cheatnet:
     name: Test Cheatnet
     env:
-      SCARB_VERSION: 0.7.0
+      SCARB_VERSION: 2.3.0
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4

.gitignore

@@ -5,4 +5,6 @@ pyproject.toml
 target
 .vscode/
 .env
+Scarb.lock
+!snforge_std/Scarb.lock
 */node_modules

CHANGELOG.md

@@ -17,6 +17,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 #### Changed
 
+- updated Cairo version to 2.3.0 - compatible Scarb version is 2.3.0:
+  - tests in `src` folder now have to be in a module annotated with `#[cfg(test)]`
 - `snforge_std::PrintTrait` will not convert values representing ASCII control characters to strings
 - separated `snforge` to subcommands: `snforge test`, `snforge init` and `snforge clean-cache`. 
 Read more [here](https://foundry-rs.github.io/starknet-foundry/appendix/forge.html).