fix: Add a splittable default value

Author: bebraw

src/plugin.ts

@@ -127,7 +127,7 @@ export default class DocgenPlugin implements webpack.WebpackPluginInstance {
     const isExcluded = matchGlob(exclude);
     const isIncluded = matchGlob(include);
     // Property compiler.version is set only starting from webpack 5
-    const webpackVersion = compiler.webpack?.version;
+    const webpackVersion = compiler.webpack?.version || "";
     const isWebpack5 = parseInt(webpackVersion.split(".")[0], 10) >= 5;
 
     compiler.hooks.compilation.tap(