Use let instead of var, fix failing test.

src/config.ts

@@ -16,14 +16,16 @@ type ConfigurationOptions = {
 
 export function readConfigFile(filePath: string = CONFIG_FILEPATH): ConfigurationOptions {
     // By default we want to fail on all severities and allow all licenses.
-    var defaultOptions: ConfigurationOptions = {
+    const defaultOptions: ConfigurationOptions = {
         fail_on_severity: "low",
         allow_licenses: ['all'],
         deny_licenses: []
     }
 
+    let data
+
     try {
-        var data = fs.readFileSync(path.resolve(filePath), "utf-8");
+        data = fs.readFileSync(path.resolve(filePath), "utf-8");
     } catch (error: any) {
         if (error.code && error.code === 'ENOENT') {
             return defaultOptions