Bump memory to 8G in build all step (#191)

Author: pebrc

.buildkite/pipeline.yml

@@ -31,7 +31,7 @@ steps:
     agents:
       image: "docker.elastic.co/ci-agent-images/eck-region/go-builder-buildkite-agent:1.23.1-1"
       cpu: "5"
-      memory: "7G"
+      memory: "8G"
 
   - label: ":helm: validate helm charts"
     command: "make validate-helm"