🌱 Update Cspo Image group to v1.21.6 (#44)

| datasource | package                  | from   | to     |
| ---------- | ------------------------ | ------ | ------ |
| docker     | docker.io/library/golang | 1.21.5 | 1.21.6 |

Co-authored-by: cluster-stack-bot[bot] <143188378+cluster-stack-bot[bot]@users.noreply.github.com>
Co-authored-by: Michal Gubricky <michal.gubricky@dnation.cloud>

images/cspo/Dockerfile

@@ -13,7 +13,7 @@
 # limitations under the License.
 
 # Build the manager binary
-FROM --platform=${BUILDPLATFORM} docker.io/library/golang:1.21.5-bullseye as build
+FROM --platform=${BUILDPLATFORM} docker.io/library/golang:1.21.6-bullseye as build
 ARG TARGETOS TARGETARCH
 
 COPY . /src/cluster-stack-provider-openstack