feat: Add TypeScript Action (#83)

cf. https://github.com/peaceiris/actions-github-pages
Close #54

.eslintrc.json

@@ -0,0 +1,24 @@
+{
+  "env": {
+    "commonjs": true,
+    "es6": true,
+    "node": true
+  },
+  "extends": [
+    "eslint:recommended",
+    "plugin:@typescript-eslint/recommended",
+    "plugin:@typescript-eslint/recommended",
+    "plugin:jest/recommended"
+  ],
+  "globals": {
+    "Atomics": "readonly",
+    "SharedArrayBuffer": "readonly"
+  },
+  "parser": "@typescript-eslint/parser",
+  "parserOptions": {
+    "sourceType": "module",
+    "ecmaVersion": 2019
+  },
+  "rules": {
+  }
+}