build: use go-version-file instead of hardcoded Go version in CI

Read Go version from go.mod so CI always stays in sync with
the project's declared Go version, matching the pattern used
in raystack/salt.

Author: ravisuhag

.github/workflows/lint.yml

@@ -11,7 +11,7 @@ jobs:
           fetch-depth: 0
       - uses: actions/setup-go@v6
         with:
-          go-version: "1.26"
+          go-version-file: "go.mod"
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v9
         with:

.github/workflows/main.yml

@@ -15,7 +15,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v6
         with:
-          go-version: "1.26"
+          go-version-file: "go.mod"
       - name: Login to DockerHub
         uses: docker/login-action@v4
         with:

.github/workflows/release.yml

@@ -16,7 +16,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v6
         with:
-          go-version: "1.26"
+          go-version-file: "go.mod"
       - name: Login to DockerHub
         uses: docker/login-action@v4
         with:

.github/workflows/test.yml

@@ -19,7 +19,7 @@ jobs:
       - uses: actions/checkout@v6
       - uses: actions/setup-go@v6
         with:
-          go-version: "1.26"
+          go-version-file: "go.mod"
       - name: Install dependencies
         run: sudo apt-get install build-essential
       - name: Install packages