Reload extension when swiftEnvironmentVariables changes (#1430)

The generated Swift build tasks are created once when the workspace
folder is added to the workspace. The environment variables are captured
at task creation time. If they're updated during the lifetime of the
extension they wont be attached to the generated tasks until the
extension restarts.

Issue: #1428

Author: plemarquand

src/extension.ts

@@ -97,9 +97,8 @@ export async function activate(context: vscode.ExtensionContext): Promise<Api> {
                     showReloadExtensionNotification(
                         "Changing the Swift path requires Visual Studio Code be reloaded."
                     );
-                }
-                // on sdk config change, restart sourcekit-lsp
-                if (
+                } else if (
+                    // on sdk config change, restart sourcekit-lsp
                     event.affectsConfiguration("swift.SDK") ||
                     event.affectsConfiguration("swift.swiftSDK")
                 ) {
@@ -108,6 +107,10 @@ export async function activate(context: vscode.ExtensionContext): Promise<Api> {
                     showReloadExtensionNotification(
                         "Changing the Swift SDK path requires the project be reloaded."
                     );
+                } else if (event.affectsConfiguration("swift.swiftEnvironmentVariables")) {
+                    showReloadExtensionNotification(
+                        "Changing environment variables requires the project be reloaded."
+                    );
                 }
             })
         );