Add javadoc

Signed-off-by: Matheus Cruz <matheuscruz.dev@gmail.com>

Author: mcruzdev

impl/core/src/main/java/io/serverlessworkflow/impl/executors/RunShellExecutor.java

@@ -156,6 +156,13 @@ public boolean accept(Class<? extends RunTaskConfiguration> clazz) {
     return RunShell.class.equals(clazz);
   }
 
+  /**
+   * Reads an InputStream and returns its content as a String. It keeps the original content using
+   * UTF-8 encoding.
+   *
+   * @param inputStream {@link InputStream} to be read
+   * @return {@link String} with the content of the InputStream
+   */
   public static String readInputStream(InputStream inputStream) {
     StringWriter writer = new StringWriter();
     try (BufferedReader reader =