add linting via eslint + bump typescript version

I gave the typescript version a fairly large bump to get eslint run.

.eslintignore

@@ -0,0 +1,5 @@
+node_modules
+dist
+coverage
+**/*.d.ts
+tests

.eslintrc.js

@@ -0,0 +1,42 @@
+module.exports = {
+    extends: [
+      'eslint:recommended',
+      'plugin:@typescript-eslint/eslint-recommended',
+      'plugin:@typescript-eslint/recommended',
+      'plugin:prettier/recommended',
+    ],
+    parser: '@typescript-eslint/parser',
+    parserOptions: {
+      project: 'tsconfig.json',
+      sourceType: 'module'
+    },
+    plugins: ['@typescript-eslint'],
+    rules: {
+      '@typescript-eslint/ban-ts-ignore': 'off', //stackoverflow.com/questions/59729654/how-ignore-typescript-errors-with-ts-ignore
+      '@typescript-eslint/camelcase': 'off',
+      '@typescript-eslint/explicit-function-return-type': 'off',
+      '@typescript-eslint/interface-name-prefix': [
+        'error',
+        { prefixWithI: 'always' },
+      ],
+      '@typescript-eslint/no-unused-vars': ['warn', { args: 'none' }],
+      '@typescript-eslint/no-explicit-any': 'off',
+      '@typescript-eslint/no-namespace': 'off',
+      '@typescript-eslint/no-this-alias': [
+        'error',
+        {
+          allowedNames: ['self'], // Allow `const self = this`
+        },
+      ],
+      '@typescript-eslint/no-use-before-define': 'off',
+      '@typescript-eslint/quotes': [
+        'error',
+        'single',
+        { avoidEscape: true, allowTemplateLiterals: false }
+      ],
+      curly: ['error', 'all'],
+      eqeqeq: 'error',
+      'prefer-arrow-callback': 'error'
+    }
+  };
+

.prettierignore

@@ -0,0 +1,4 @@
+node_modules
+**/node_modules
+**/lib
+**/package.json

.prettierrc

@@ -0,0 +1,3 @@
+{
+  "singleQuote": true
+}