Update VSCode / Github Codespaces workflow

.devcontainer/devcontainer.json

 {
-  "postCreateCommand": "sudo apt-get update && sudo apt-get -y --no-install-recommends install cmake"
+  "postCreateCommand": "bash .devcontainer/setup.sh"
 }

.devcontainer/setup.sh

+#!/bin/sh
+set -e
+
+sudo apt-get update
+sudo apt-get -y --no-install-recommends install cmake
+
+mkdir build
+cd build
+cmake ..
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.vscode/launch.json

+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "(gdb) Launch",
+            "type": "cppdbg",
+            "request": "launch",
+            "program": "${workspaceFolder}/build/libgit2_clar",
+            "args": [],
+            "stopAtEntry": false,
+            "cwd": "${fileDirname}",
+            "environment": [],
+            "externalConsole": false,
+            "MIMode": "gdb",
+            "setupCommands": [
+                {
+                    "description": "Enable pretty-printing for gdb",
+                    "text": "-enable-pretty-printing",
+                    "ignoreFailures": true
+                }
+            ]
+        }
+    ]
+}
\ No newline at end of file

.vscode/tasks.json

+{
+    // See https://go.microsoft.com/fwlink/?LinkId=733558
+    // for the documentation about the tasks.json format
+    "version": "2.0.0",
+    "tasks": [
+      {
+        "label": "Build",
+        "type": "shell",
+        "command": "cd build && cmake --build .",
+        "group": "build",
+        "presentation": {
+          "reveal": "always",
+          "panel": "new"
+        }
+      },
+      {
+        "label": "Run Tests",
+        "type": "shell",
+        "command": "build/libgit2_clar -v",
+        "group": "test",
+        "presentation": {
+          "reveal": "always",
+          "panel": "new"
+        }
+      }
+    ]
+  }
\ No newline at end of file