feat: add upsert method

Most `PropertiesEditor` methods now return booleans depending on the result of each action.

BREAKING CHANGE: - re-aligned method names to be closer to SQL conventions since using `upsert`
  - the `PropertiesEditor` `remove` method was renamed to `delete`
  - the `PropertiesEditor` `edit` method was renamed to `update`

README.md

@@ -167,7 +167,7 @@ properties.insert('newKey2', 'こんにちは', {
   escapeUnicode: true,
 })
 
-properties.remove('hello')
+properties.delete('hello')
 console.log(properties.format())
 
 /**
@@ -184,6 +184,8 @@ console.log(properties.format())
  */
 ```
 
+We were not able to show all methods in the example, but the `update` and `upsert` methods can also be useful to modify content.
+
 ### Webpack File Loader
 
 If you would like to import `.properties` directly using `import`, this package comes with its own Webpack file loader located under `properties-file/webpack-loader`. Here is an example of how to configure it:

package.json

@@ -65,8 +65,8 @@
   "devDependencies": {
     "@release-it/conventional-changelog": "5.1.1",
     "@types/jest": "29.5.1",
-    "@typescript-eslint/eslint-plugin": "5.59.0",
-    "@typescript-eslint/parser": "5.59.0",
+    "@typescript-eslint/eslint-plugin": "5.59.1",
+    "@typescript-eslint/parser": "5.59.1",
     "dotenv-cli": "7.2.1",
     "eslint": "8.39.0",
     "eslint-config-prettier": "8.8.0",