chore(deps): update grafana/shared-workflows/build-push-to-dockerhub action to v0.3.0

| datasource  | package                  | from                           | to                             |
| ----------- | ------------------------ | ------------------------------ | ------------------------------ |
| github-tags | grafana/shared-workflows | build-push-to-dockerhub/v0.2.0 | build-push-to-dockerhub/v0.3.0 |


Signed-off-by: renovate-sh-app[bot] <219655108+renovate-sh-app[bot]@users.noreply.github.com>

Author: renovate-sh-app[bot]

.github/workflows/build.yml

@@ -45,7 +45,7 @@ jobs:
           persist-credentials: false
 
       - name: Build Docker image
-        uses: grafana/shared-workflows/actions/build-push-to-dockerhub@1acd69f48c01d7aef5f209f94048dfeb789026db # build-push-to-dockerhub/v0.2.0
+        uses: grafana/shared-workflows/actions/build-push-to-dockerhub@06f8765f6a5043b01e5a3dddd78a71741552add7 # build-push-to-dockerhub/v0.3.0
         with:
           platforms: linux/amd64,linux/arm64
           push: ${{ github.event_name == 'push' || github.event_name == 'workflow_call' }}