Fix dependencies

pyproject.toml

@@ -5,19 +5,19 @@ version = "0.0.0"
 description = "Package for managing codelists & attributes for IAMC-format datasets"
 license = "APACHE-2.0"
 readme = "README.md"
-
-[project.dependencies]
-python = ">=3.10, <3.13"
-click = ">= 8"
-pyam-iamc = ">= 2.1"
-openpyxl = "^3.1.2"
-pydantic = "^2"
-PyYAML = "^6.0.1"
-pandas = ">=1.5.2"
-pycountry = "23.12.11"  # pin to guard against "silent" changes in country names
-pysquirrel = "^1.1"
-gitpython = "^3.1.40"
-numpy = ">=1.23.0"
+dependencies = [
+    python = ">=3.10, <3.13",
+    click = ">= 8",
+    pyam-iamc = ">= 2.1",
+    openpyxl = "^3.1.2",
+    pydantic = "^2",
+    PyYAML = "^6.0.1",
+    pandas = ">=1.5.2",
+    pycountry = "23.12.11",
+    pysquirrel = "^1.1",
+    gitpython = "^3.1.40",
+    numpy = ">=1.23.0"
+]
 
 [project.scripts]
 nomenclature = 'nomenclature.cli:cli'