Support python 3.7

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "litexcnc"
-version = "0.9.0a3"
+version = "0.9.0a4"
 description = "Generic CNC firmware and driver for FPGA cards which are supported by LiteX"
 authors = ["Peter van Tol <[email protected]>"]
 license = "GPL-3.0-or-later"
@@ -27,6 +27,7 @@ classifiers = [
     "Operating System :: POSIX :: Linux",
     "Programming Language :: Other",
     "Programming Language :: Python :: 3 :: Only",
+    "Programming Language :: Python :: 3.7",
     "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
@@ -35,7 +36,7 @@ classifiers = [
 ]
 
 [tool.poetry.dependencies]
-python = "^3.8"
+python = "^3.7"
 packaging = "^21.3"
 pydantic = "^1.10.2"
 requests = {version="^2.28.1", optional = true}