Add GH CLI to devcontainer

.devcontainer/Dockerfile

@@ -0,0 +1,6 @@
+FROM mcr.microsoft.com/vscode/devcontainers/python:0-3.8
+ENV DEBIAN_FRONTEND=noninteractive
+RUN apt-get update \
+    \
+    && wget -O /tmp/github-debian.sh https://raw.githubusercontent.com/microsoft/vscode-dev-containers/master/script-library/github-debian.sh \
+    && bash /tmp/github-debian.sh

.devcontainer/devcontainer.json

@@ -1,6 +1,7 @@
 {
-  "image": "mcr.microsoft.com/vscode/devcontainers/python:0-3.8",
-  "context": "..",
+	"build": {
+		"dockerfile": "Dockerfile",
+	},
   "extensions": [
     "ms-python.python",
     "ms-python.vscode-pylance",