ci/gha: remove actions/cache

Because actions/setup-go does its own caching now, adding our own:
 - unnecessarily complicates things;
 - results in double caching.

Remove it.

Note that a single common cache will be used between the two jobs (which
is OK).

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

Author: kolyshkin

.github/workflows/integration.yml

@@ -10,17 +10,10 @@ jobs:
   conmon:
     runs-on: ubuntu-latest
     steps:
+      - uses: actions/checkout@v4
       - uses: actions/setup-go@v5
         with:
           go-version: '1.22'
-      - uses: actions/checkout@v4
-      - uses: actions/cache@v4
-        with:
-          path: |
-            ~/go/pkg/mod
-            ~/.cache/go-build
-          key: go-integration-conmon-${{ hashFiles('**/go.mod') }}
-          restore-keys: go-integration-conmon-
       - run: sudo hack/github-actions-setup
       - name: Run conmon integration tests
         run: |
@@ -31,17 +24,10 @@ jobs:
   cri-o:
     runs-on: ubuntu-latest
     steps:
+      - uses: actions/checkout@v4
       - uses: actions/setup-go@v5
         with:
           go-version: '1.22'
-      - uses: actions/checkout@v4
-      - uses: actions/cache@v4
-        with:
-          path: |
-            ~/go/pkg/mod
-            ~/.cache/go-build
-          key: go-integration-cri-o-${{ hashFiles('**/go.mod') }}
-          restore-keys: go-integration-cri-o-
       - run: sudo hack/github-actions-setup
       - name: Run CRI-O integration tests
         run: |