Prevent renovate from updating snakeyaml-engine to v3 (#15277)

Author: laurit

.github/renovate.json5

@@ -159,6 +159,16 @@
         'com.github.tomakehurst:wiremock-jre8'
       ],
     },
+    {
+      // snakeyaml-engine 3+ requires Java 11+
+      matchUpdateTypes: [
+        'major',
+      ],
+      enabled: false,
+      matchPackageNames: [
+        'org.snakeyaml:snakeyaml-engine'
+      ],
+    },
     {
       // vaadin 14 tests require node 16
       matchPackageNames: [