Add GitHub CLI feature to devcontainer

Author: pamelafox

.devcontainer/devcontainer.json

@@ -6,7 +6,8 @@
     "forwardPorts": [5432, 6379, 18888],
     "features": {
         "ghcr.io/azure/azure-dev/azd:latest": {},
-        "ghcr.io/devcontainers/features/azure-cli:latest": {}
+        "ghcr.io/devcontainers/features/azure-cli:latest": {},
+        "ghcr.io/devcontainers/features/github-cli:1": {}
     },
     "customizations": {
         "vscode": {