Changed supported python versions (#86)

* Updated pyproject.toml to support Python >= 3.9
* Updated tests to be performed for Python >= 3.9

Author: LukasFehring

.github/workflows/tests.yml

@@ -8,7 +8,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ "ubuntu-latest", "macos-latest", "windows-latest" ]
-        python-version: [ "3.7", "3.8", "3.9", ]
+        python-version: ["3.9", ]
     defaults:
       run:
         shell: bash

.vscode/settings.json

@@ -51,5 +51,6 @@
 		"**/.git/objects/**": true,
 		"**/.git/subtree-cache/**": true,
 		"**/node_modules/*/**": true
-	}
+	},
+	"esbonio.sphinx.confDir": "${workspaceFolder}\\docs"
 }