chore(renovate): add docker-build-push-multiarch for auto updates (#1515)

Author: ricky-undeadcoders

.github/renovate.json5

@@ -12,6 +12,13 @@
         "# renovate: datasource=(?<datasource>[a-z-.]+?) depName=(?<depName>[^\\s]+?)(?: (?:lookupName|packageName)=(?<packageName>[^\\s]+?))?(?: versioning=(?<versioning>[^\\s]+?))?(?: extractVersion=(?<extractVersion>[^\\s]+?))?\\s+[A-Za-z0-9_-]+[_-](?:VERSION|version)\\s*[:=]\\s*[\"']?(?<currentValue>[^\"'@\\n]+)(?:@(?<currentDigest>sha256:[a-f0-9]+))?[\"']?",
       ],
     },
+    {
+      customType: "regex",
+      managerFilePatterns: [
+        "/(?:^|/)\\.github/workflows/docker-build-push-multiarch.yml",
+      ],
+      datasourceTemplate: "github-actions",
+    },
     {
       customType: "regex",
       managerFilePatterns: ["/(?:^|/)actions/.+/action\\.ya?ml$/"],