Cache Go modules explicitly with go mod download

Add go mod download step after setup-go in all CI jobs to ensure the
module cache is populated as a discrete step. This makes cache hits visible
in logs and prevents module downloads from being interleaved with build
operations, improving cache effectiveness.

Signed-off-by: Bryan Frimin <bryan@getprobo.com>

.github/workflows/release.yaml

@@ -31,6 +31,8 @@ jobs:
           go-version: "1.26.1"
           cache: true
 
+      - run: "go mod download"
+
       - name: Set up Node.js
         uses: actions/setup-node@v6
         with: