title: Angular Form exact 10 alphanumeric letters pattern validation
body: <p>I have the following problem with this specific use case of a reactive form field validation.</p>
  <p>At the moment I only set this rule:</p>
  <pre><code>this.projectForm = this.fb.group({
    .....................................................................................,
    .....................................................................................,
    .....................................................................................,
    CIG: [null, [Validators.required, Validators.minLength(10),Validators.maxLength(10)]],
  </code></pre>
  <p>at the moment I am checking if the value inserted into my <strong>CIG</strong> form field have exactly 10 charachers as lenght.</p>
  <p>My problem is that I have to check also that this is an alphanumeric string (composed of exactly 10 characters).</p>
  <p>So something like this is allowed: <strong>ABCED12345</strong> but somethint like this is not allowed: <strong>ABCD-12345</strong></p>
  <p>How can I implement this behavior using <strong>Validators</strong>? I need to use REGEX or something like this?</p>