Switch ts and eslint to use 2021 version (#281)

Author: bmish

.eslintrc.cjs

@@ -1,7 +1,7 @@
 module.exports = {
   root: true,
   parserOptions: {
-    ecmaVersion: 2020,
+    ecmaVersion: 2021,
     sourceType: 'module',
   },
   plugins: ['square'],

tsconfig.json

@@ -7,7 +7,7 @@
     "declaration": true,
     "experimentalDecorators": true,
     "lib": [
-      "es2020"
+      "es2021"
     ],
     "module": "ES2020",
     "moduleResolution": "node",
@@ -22,7 +22,7 @@
         "types/*"
       ]
     },
-    "target": "es2020",
+    "target": "es2021",
     "types": ["node"],
     "typeRoots": ["./types"]
   },