Remove "node_modules" (#57)

It's needed only on the release branch. No need to pollute development
branches with that. CI is able to "npm install" it back.

node_modules/@actions/core/package.json

@@ -1,46 +0,0 @@
-{
-  "name": "@actions/core",
-  "version": "1.9.1",
-  "description": "Actions core lib",
-  "keywords": [
-    "github",
-    "actions",
-    "core"
-  ],
-  "homepage": "https://github.com/actions/toolkit/tree/main/packages/core",
-  "license": "MIT",
-  "main": "lib/core.js",
-  "types": "lib/core.d.ts",
-  "directories": {
-    "lib": "lib",
-    "test": "__tests__"
-  },
-  "files": [
-    "lib",
-    "!.DS_Store"
-  ],
-  "publishConfig": {
-    "access": "public"
-  },
-  "repository": {
-    "type": "git",
-    "url": "git+https://github.com/actions/toolkit.git",
-    "directory": "packages/core"
-  },
-  "scripts": {
-    "audit-moderate": "npm install && npm audit --json --audit-level=moderate > audit.json",
-    "test": "echo \"Error: run tests from root\" && exit 1",
-    "tsc": "tsc"
-  },
-  "bugs": {
-    "url": "https://github.com/actions/toolkit/issues"
-  },
-  "dependencies": {
-    "@actions/http-client": "^2.0.1",
-    "uuid": "^8.3.2"
-  },
-  "devDependencies": {
-    "@types/node": "^12.0.2",
-    "@types/uuid": "^8.3.4"
-  }
-}