ci(deps): bump renovate docker tag to v37.421.6 (#829)

| datasource | package                      | from     | to       |
| ---------- | ---------------------------- | -------- | -------- |
| docker     | ghcr.io/renovatebot/renovate | 37.421.3 | 37.421.6 |

Co-authored-by: mazi-renovate[bot] <161091290+mazi-renovate[bot]@users.noreply.github.com>

.github/workflows/renovate.yml

@@ -14,7 +14,7 @@ env:
   config_file: config.yaml
   # tool versions
   # renovate: datasource=docker depName=renovate packageName=ghcr.io/renovatebot/renovate
-  RENOVATE_VERSION: 37.421.3
+  RENOVATE_VERSION: 37.421.6
 
 jobs:
   renovate: