Update setup.py so it can be run on python 3.7

setup.py

@@ -8,7 +8,8 @@ REQUIREMENTS = [
     'dataclasses;python_version<"3.7"',
     'jsonnet==0.15.0',
     'filelock==3.0',
-    'numpy==1.22.0',
+    'numpy==1.22.0;python_version>="3.8"',
+    'numpy==1.21.6;python_version<"3.8"',
     'overrides==3.1.0',
     'requests==2.23.0',
     'sentencepiece==0.1.83;python_version<"3.8"',
@@ -35,10 +36,11 @@ setup(
     url='https://gitlab.clarin-pl.eu/syntactic-tools/combo',
     keywords="nlp natural-language-processing dependency-parsing",
     setup_requires=['pytest-runner',
-    		    'pytest-pylint',
-                'scikit-learn==0.23.2',
-    		    'numpy==1.22.0',
-    		    'scipy==1.6.0;python_version>="3.7"'],
+    		        'pytest-pylint',
+                    'scikit-learn==0.23.2',
+    		        'numpy==1.22.0;python_version>="3.8"',
+                    'numpy==1.21.6;python_version<"3.8"',
+    		        'scipy==1.6.0;python_version>="3.7"'],
     tests_require=['pytest', 'pylint'],
     python_requires='>=3.6',
     package_data={'combo': ['config.graph.template.jsonnet', 'config.template.jsonnet']},