docs: fix repology sample (#12192)

lib/datasource/repology/readme.md

@@ -16,7 +16,7 @@ A real world example for this specific datasource would be maintaining system pa
     {
       "fileMatch": ["^Dockerfile$"],
       "matchStrings": [
-        "#\\s*renovate:\\s*datasource=(?<datasource>.*?) depName=(?<depName>.*?)( versioning=(?<versioning>.*?))?\\sENV .*?_VERSION=(?<currentValue>.*)\\s"
+        "#\\s*renovate:\\s*datasource=(?<datasource>.*?) depName=(?<depName>.*?)( versioning=(?<versioning>.*?))?\\sENV .*?_VERSION=\"(?<currentValue>.*)\"\\s"
       ],
       "versioningTemplate": "{{#if versioning}}{{{versioning}}}{{else}}semver{{/if}}"
     }