Adapt GitHub workflows from tc39/proposal-temporal

Use a recent version of node for these actions instead of running it on
several different versions; remove anything related to spec text, test262,
or cookbook.

Author: ptomato

.github/workflows/lint.yml

@@ -0,0 +1,13 @@
+name: Run linter
+on: pull_request
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: use node.js v15.x
+        uses: actions/setup-node@v1
+        with:
+          node-version: 15.x
+      - run: npm ci --no-optional
+      - run: npm run lint

.github/workflows/test.yml

@@ -0,0 +1,17 @@
+name: Run tests
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: use node.js v15.x
+        uses: actions/setup-node@v1
+        with:
+          node-version: 15.x
+      - run: npm ci --no-optional
+      - run: npm test

.gitignore

@@ -1,4 +1,3 @@
-package-lock.json
 node_modules/
 dist/
 .eslintcache