minor symfony#36980 [Form] add missing Czech validators translation (mhujer)

This PR was merged into the 3.4 branch.

Discussion
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[Form] add missing Czech validators translation

| Q             | A
| ------------- | ---
| Branch?       | 5.1
| Bug fix?      | yes
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| License       | MIT

Commits
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afdda5d [Form] add missing Czech validators translation

Author: fabpot

src/Symfony/Component/Form/Resources/translations/validators.cs.xlf

@@ -14,6 +14,10 @@
                 <source>The CSRF token is invalid. Please try to resubmit the form.</source>
                 <target>CSRF token je neplatný. Zkuste prosím znovu odeslat formulář.</target>
             </trans-unit>
+            <trans-unit id="99">
+                <source>This value is not a valid HTML5 color.</source>
+                <target>Tato hodnota není platná HTML5 barva.</target>
+            </trans-unit>
         </body>
     </file>
 </xliff>