Removed support for Python 3.6 (#856)

.github/workflows/test.yml

@@ -21,8 +21,8 @@ jobs:
         python: ["3.7", "3.8", "3.9", "3.10", "3.11"]
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-python@v3
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python }}
       - name: Setup Graphviz

README.md

@@ -41,7 +41,7 @@ Diagrams lets you draw the cloud system architecture **in Python code**. It was
 
 ## Getting Started
 
-It requires **Python 3.6** or higher, check your Python version first.
+It requires **Python 3.7** or higher, check your Python version first.
 
 It uses [Graphviz](https://www.graphviz.org/) to render the diagram, so you need to [install Graphviz](https://graphviz.gitlab.io/download/) to use **diagrams**. After installing graphviz (or already have it), install the **diagrams**.
 

pyproject.toml

@@ -13,7 +13,6 @@ include = ["resources/**/*"]
 python = "^3.7"
 graphviz = ">=0.13.2,<0.21.0"
 jinja2 = ">=2.10,<4.0"
-contextvars = { version = "^2.4", python = "~3.6" }
 typed-ast = "^1.5.4"
 
 [tool.poetry.dev-dependencies]