bump poetry-core build requirement to >=1.2

pyproject.toml

@@ -26,7 +26,7 @@ generate-setup-file = true
 requires = [
     "setuptools>=58.0.0,<69.0.0",
     "pybind11>=2.10.0",
-    "poetry-core",     # >=1.0",
+    "poetry-core>=1.2",     # >=1.0",
     "lark>=1.0.0",     # required for C++ compilation during
     "appdirs>=1.4.0",  # installation using functionality of endf-parserpy
 ]