Change Python minimum version 3.7 -> 3.8

pyproject.toml

@@ -4,7 +4,7 @@ description="CPU implementation of operators of the AIDGE framework"
 dependencies = [
     "numpy",
 ]
-requires-python = ">= 3.7"
+requires-python = ">= 3.8"
 readme = "README.md"
 license = { file = "LICENSE" }
 classifiers = [