Merge pull request #410 from cpanato/alpine

dockerfile: update alpine base image to the latest to fix any security issues

Author: Timo Reimann

cloud-controller-manager/cmd/digitalocean-cloud-controller-manager/Dockerfile

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM alpine:3.6
+FROM alpine:3.15
 
 RUN apk add --no-cache ca-certificates