feat(config): add option to force require config files

- Added `forceRequire` parameter to `parseConfig` and `importConfig` functions.
- Enabled forcing the use of `require()` for configuration files, regardless of their extension.
- Improved compatibility with Windows by replacing backslashes with forward slashes when using `import()`.

lib/config.js

@@ -265,7 +265,7 @@ function configChecker({ config, file }) {
  * @see     {@link module:config~importConfig importConfig}
  *          (alias for <code>parseConfig(config, true)</code>)
  */
-function parseConfig(configFile, resolve=true) {
+function parseConfig(configFile, resolve=true, forceRequire=false) {
   function resolveOrCheckOnly(config) {
     // Attempt to extract the default export (only on ES module) if the configuration
     // object only contains that 'default' property, for clarity:
@@ -294,15 +294,17 @@ function parseConfig(configFile, resolve=true) {
     }`);
   }
 
-  // Resolve the configuration file path
-  configFile = path.resolve(configFile);
-
   // Import the configuration file
   let config = null;
   // Only include '.cjs' and '.json' to use require()
-  if (KNOWN_CONFIG_EXTS.slice(2).includes(path.extname(configFile))) {
+  if (KNOWN_CONFIG_EXTS.slice(2).includes(path.extname(configFile))
+      || forceRequire) {
     config = require(configFile);
   } else {
+    // On Windows, replace all '\' with '/' to use import()
+    if (process.platform === 'win32') {
+      configFile = 'file:///' + configFile.replace(/\\/g, '/');
+    }
     config = import(configFile);
   }
 
@@ -328,7 +330,7 @@ function parseConfig(configFile, resolve=true) {
  * @since  1.0.0
  * @see    {@link module:config~parseConfig parseConfig}
  */
-const importConfig = (file) => parseConfig(file, true);
+const importConfig = (file, forceRequire=false) => parseConfig(file, true, forceRequire);
 
 
 module.exports = Object.freeze({