Rename webpack.extensions.ts to webpack.extension-api.ts to avoid confusion

Signed-off-by: Hung-Han (Henry) Chen <1474479+chenhunghan@users.noreply.github.com>

package.json

@@ -20,7 +20,7 @@
     "compile": "env NODE_ENV=production concurrently yarn:compile:*",
     "compile:main": "yarn run webpack --config webpack.main.ts",
     "compile:renderer": "yarn run webpack --config webpack.renderer.ts",
-    "compile:extension-types": "yarn run webpack --config webpack.extensions.ts",
+    "compile:extension-types": "yarn run webpack --config webpack.extension-api.ts",
     "npm:fix-package-version": "yarn run ts-node build/set_npm_version.ts",
     "build:linux": "yarn run compile && electron-builder --linux --dir -c.productName=Lens",
     "build:mac": "yarn run compile && electron-builder --mac --dir -c.productName=Lens",