Update Go version in nightly parallel integration tests workflow

Author: cx-amol-mane

.github/workflows/nightly-parallel.yml

@@ -251,7 +251,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@4d34df0c2316fe8122ab82dc22947d607c0c91f9 #v4
         with:
-          go-version-file: go.mod
+          go-version: '1.25.x'
 
       - name: Build binary
         run: go build -o ./bin/cx ./cmd
@@ -405,7 +405,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@4d34df0c2316fe8122ab82dc22947d607c0c91f9 #v4
         with:
-          go-version-file: go.mod
+          go-version: '1.25.x'
 
       - name: Install gocovmerge
         run: go install github.com/wadey/gocovmerge@latest