Move --sourcemap to scripts instead of Invoke-Build

So that they're generated even when using `build-watch`. Double-checked
that they're not included in the package (even though they're now
generated for release configuration too).

package.json

@@ -118,7 +118,7 @@
   "main": "./out/main.js",
   "scripts": {
     "lint": "eslint . --ext .ts",
-    "build": "esbuild ./src/main.ts --outdir=out --bundle --external:vscode --platform=node",
+    "build": "esbuild ./src/main.ts --outdir=out --sourcemap --bundle --external:vscode --platform=node",
     "build-watch": "npm run build -- --watch",
     "build-test": "tsc --incremental",
     "build-test-watch": "npm run build-test -- --watch",

vscode-powershell.build.ps1

@@ -101,7 +101,7 @@ task Build Restore, {
     # Unfortunately `esbuild` doesn't support emitting 1:1 files (yet).
     # https://github.com/evanw/esbuild/issues/944
     switch ($Configuration) {
-        "Debug" { Invoke-BuildExec { & npm run build -- --sourcemap } }
+        "Debug" { Invoke-BuildExec { & npm run build } }
         "Release" { Invoke-BuildExec { & npm run build -- --minify } }
     }
 }