Chore: Update ghcr.io/renovatebot/renovate Docker tag to v39.48.0

Author: grafanarenovatebot[bot]

.github/workflows/renovate-validate.yaml

@@ -13,5 +13,5 @@ jobs:
       - name: Validate renovate config
         run: |-
           # Renovate updates the line below. Please keep its formatting as it is.
-          export RENOVATE_IMAGE=ghcr.io/renovatebot/renovate:39.38.0@sha256:5a53ef5d0488e54ad36194453f012cce7926660d46076e424053d445d4ff0225
+          export RENOVATE_IMAGE=ghcr.io/renovatebot/renovate:39.48.0@sha256:b52c13d951e76e12c700ad5c65e3c5ef7bfbf8c777e3c43c9287ba0a489627e4
           docker run -i --rm -v $(realpath .):/repo -w /repo --entrypoint renovate-config-validator "$RENOVATE_IMAGE" --strict

.github/workflows/renovate.yaml

@@ -37,7 +37,7 @@ jobs:
       - name: Self-hosted Renovate
         uses: renovatebot/github-action@dd4d265eb8646cd04fc5f86ff8bc8d496d75a251 # v40.2.8
         with:
-          renovate-version: 39.38.0@sha256:5a53ef5d0488e54ad36194453f012cce7926660d46076e424053d445d4ff0225
+          renovate-version: 39.48.0@sha256:b52c13d951e76e12c700ad5c65e3c5ef7bfbf8c777e3c43c9287ba0a489627e4
           configurationFile: .github/renovate-app.json
           token: "${{ steps.app-token.outputs.token }}"
         env: