improvement(vscode): parse GCC diagnostics

Updated the vscode build task to parse warnings/errors from GCC.

.vscode/tasks.json

@@ -10,7 +10,13 @@
       "group": {
         "kind": "build",
         "isDefault": true
-      }
+      },
+      "problemMatcher": [
+        {
+          "base": "$gcc",
+          "fileLocation": ["autoDetect", "${workspaceFolder}/app/build"]
+        }
+      ]
     },
     {
       "label": "Flash",