feat(logger): Count warnings (#1205)

If you want to make your build fail on error messages, you currently can do

```
const result = app.generateDocs(project, OUTPUT_DIR);
if (!result || app.logger.hasErrors() ) {
  console.log("Errors were logged during the generation of the documentation. Check the log for more information");
  process.exit(1);
}
```

However, warning messages typically indicate a problem as well. If you want to make your build fail on those as well, you need a custom logger to keep track of the warning messages yourself.

This PR makes this easier by counting the warning messages in a similar fashion as the error messages.

src/lib/utils/loggers.ts

@@ -24,20 +24,39 @@ export class Logger {
  */
  errorCount = 0;
 
+ /**
+ * How many warning messages have been logged?
+ */
+ warningCount = 0;
+
  /**
  * Has an error been raised through the log method?
  */
  public hasErrors(): boolean {
  return this.errorCount > 0;
  }
 
+ /**
+ * Has a warning been raised through the log method?
+ */
+ public hasWarnings(): boolean {
+ return this.warningCount > 0;
+ }
+
  /**
  * Reset the error counter.
  */
  public resetErrors() {
  this.errorCount = 0;
  }
 
+ /**
+ * Reset the warning counter.
+ */
+ public resetWarnings() {
+ this.warningCount = 0;
+ }
+
  /**
  * Log the given message.
  *
@@ -109,6 +128,9 @@ export class Logger {
  if (level === LogLevel.Error) {
  this.errorCount += 1;
  }
+ if (level === LogLevel.Warn) {
+ this.warningCount += 1;
+ }
  }
 
  /**