Validate dev cluster config in CI (grafana#11642)

**What this PR does / why we need it**:
The configuration in `tools/dev/loki-boltdb-storage-s3` was broken in
the past because it's easy to miss. This change covers the validation in
the CI to raise awareness.

**Checklist**
- [ ] Reviewed the
[`CONTRIBUTING.md`](https://github.com/grafana/loki/blob/main/CONTRIBUTING.md)
guide (**required**)
- [ ] Documentation added
- [ ] Tests updated
- [ ] `CHANGELOG.md` updated
- [ ] If the change is worth mentioning in the release notes, add
`add-to-release-notes` label
- [ ] Changes that require user attention or interaction to upgrade are
documented in `docs/sources/setup/upgrade/_index.md`
- [ ] For Helm chart changes bump the Helm chart version in
`production/helm/loki/Chart.yaml` and update
`production/helm/loki/CHANGELOG.md` and
`production/helm/loki/README.md`. [Example
PR](grafana@d10549e)
- [ ] If the change is deprecating or removing a configuration option,
update the `deprecated-config.yaml` and `deleted-config.yaml` files
respectively in the `tools/deprecated-config-checker` directory.
[Example
PR](grafana@0d4416a)

.drone/drone.jsonnet

@@ -640,6 +640,7 @@ local build_image_tag = '0.33.0';
         'GIT_TARGET_BRANCH="$DRONE_TARGET_BRANCH"',
       ]) { depends_on: ['loki'], when: onPRs },
       make('validate-example-configs', container=false) { depends_on: ['loki'] },
+      make('validate-dev-cluster-config', container=false) { depends_on: ['loki'] },
       make('check-example-config-doc', container=false) { depends_on: ['clone'] },
       {
         name: 'build-docs-website',

.drone/drone.yml

@@ -303,6 +303,13 @@ steps:
   environment: {}
   image: grafana/loki-build-image:0.33.0
   name: validate-example-configs
+- commands:
+  - make BUILD_IN_CONTAINER=false validate-dev-cluster-config
+  depends_on:
+  - loki
+  environment: {}
+  image: grafana/loki-build-image:0.33.0
+  name: validate-dev-cluster-config
 - commands:
   - make BUILD_IN_CONTAINER=false check-example-config-doc
   depends_on:
@@ -2106,6 +2113,6 @@ kind: secret
 name: gpg_private_key
 ---
 kind: signature
-hmac: 30f2fb121d8271e00dc2ae8fe83a32e0e22fd2bd268609d0c3f295033fcd4fb6
+hmac: fe7669a21410ae5f2d1ad6b6205fdc582af874f65f7bd6a679731a88174e3a1c
 
 ...

Makefile

@@ -801,6 +801,9 @@ EXAMPLES_SKIP_VALIDATION_FLAG := "doc-example:skip-validation=true"
 validate-example-configs: loki
 	for f in $$(grep -rL $(EXAMPLES_SKIP_VALIDATION_FLAG) $(EXAMPLES_YAML_PATH)/*.yaml); do echo "Validating provided example config: $$f" && ./cmd/loki/loki -config.file=$$f -verify-config || exit 1; done
 
+validate-dev-cluster-config: loki
+	./cmd/loki/loki -config.file=./tools/dev/loki-boltdb-storage-s3/config/loki.yaml -verify-config
+
 # Dynamically generate ./docs/sources/configure/examples.md using the example configs that we provide.
 # This target should be run if any of our example configs change.
 generate-example-config-doc: