Merge pull request #81 from rajbos:container

Universal image is using deprecated version, switch to custom container

Author: rajbos

.devcontainer/Dockerfile

@@ -0,0 +1,4 @@
+FROM mcr.microsoft.com/powershell:7.3-alpine-3.17
+
+# add git
+RUN apk add --no-cache git

.devcontainer/devcontainer.json

@@ -1,10 +1,18 @@
 {
     "name": "PowerShell",
-    "image": "mcr.microsoft.com/powershell:latest",
-    "settings": { 
-        "terminal.integrated.shell.linux": "/usr/bin/pwsh"
+    "build": {
+        "dockerfile": "Dockerfile"
     },
-    "extensions": [
-        "ms-vscode.powershell"
-    ]
+    "customizations": {
+        "settings": { 
+            "terminal.integrated.shell.linux": "/usr/bin/pwsh"
+        },
+        "vscode": {
+            "extensions": [
+                "ms-azuretools.vscode-docker",
+                "ms-vscode.powershell",
+                "GitHub.copilot"
+            ]
+        }
+    }
 }