fuzz: Fix cache path

Signed-off-by: Paulo Gomes <paulo.gomes@weave.works>

.github/workflows/cifuzz.yaml

@@ -21,12 +21,15 @@ jobs:
       uses: actions/setup-go@v3
       with:
         go-version: 1.18.x
+    - id: go-env
+      run: |
+        echo "::set-output name=go-mod-cache::$(go env GOMODCACHE)"
     - name: Restore Go cache
       uses: actions/cache@v3
       with:
-        path: /home/runner/work/_temp/_github_home/go/pkg/mod
+        path: ${{ steps.go-env.outputs.go-mod-cache }}
         key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
         restore-keys: |
-          ${{ runner.os }}-go-
+          ${{ runner.os }}-go
     - name: Smoke test Fuzzers
       run: make fuzz-smoketest