Be more explicit about minimum requirements on zfit for tests

Author: eduardo-rodrigues

pyproject.toml

@@ -68,10 +68,10 @@ test = [
     "pytest",
     "pytest-cov",
     "pytest-runner",
-    "zfit>=0.20.0;python_version<'3.13'",
+    "zfit>=0.27.0;python_version<'3.14'",
 #    'hepstats[zfit];python_version<"3.13"',  # not working, why?
 ]
-zfit = ["zfit>=0.20.0"]
+zfit = ["zfit>=0.27.0"]