Find / stash (new) gocache (#620)

- (In)validate cache by branch

.circleci/config.yml

@@ -58,6 +58,7 @@ jobs:
       MINIKUBE_WANTUPDATENOTIFICATION: false
       MINIKUBE_WANTREPORTERRORPROMPT: false
       SKAFFOLD_VERSION: v0.18.0
+      GOCACHE: /home/circleci/.cache/go
     steps:
       - checkout
       - run:
@@ -99,17 +100,28 @@ jobs:
           name: Watch nodes
           command: kubectl get nodes -o json --watch
           background: true
+
       - restore_cache:
           keys:
-            - v1-pkg-cache
+            - pkg-cache-{{ .Branch }}
+            - go-cache-{{ .Branch }}
+
       - run:
           name: Run the end-to-end test suite
           command: |
             make e2e
+
       - save_cache:
-          key: v1-pkg-cache
+          key: pkg-cache-{{ .Branch }}
           paths:
             - "/go/pkg"
+            - "/home/circleci/go/"
+
+      - save_cache:
+          key: go-cache-{{ .Branch }}
+          paths:
+            - "/home/circleci/.cache/go"
+
       - run:
           name: Collect logs on failure from vkubelet-mock-0
           command: |