build(deps-dev): update altair requirement from <5.0,>=4.0 to >=4.0,<6.0

Updates the requirements on [altair](https://github.com/altair-viz/altair) to permit the latest version.
- [Release notes](https://github.com/altair-viz/altair/releases)
- [Commits](vega/altair@v4.0.0...v5.0.0)

---
updated-dependencies:
- dependency-name: altair
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

pyproject.toml

@@ -59,7 +59,7 @@ write_to = "src/embcompare/_version.py"
 gui = [
     "streamlit>=1.12,<2",
     "pandas>=1.3,<3.0",
-    "altair>=4.0,<5.0",
+    "altair>=4.0,<6.0",
     "loguru>=0.6,<1.0",
 ]
 dev = [