ci: drop dead golint step, align Go to go.mod 1.25, bump checkout to v4

ci.yaml installed golang.org/x/lint/golint but never invoked it; golint has been deprecated and frozen since 2021. The CI Go version (1.24.2) also lagged the go.mod directive (1.25). Remove the dead step, align both workflows to Go 1.25, and bump the remaining actions/checkout@v3 usages to v4 (release.yaml was already on v4).

.github/workflows/ci.yaml

@@ -10,15 +10,12 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout Code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Set up Go
         uses: actions/setup-go@v4
         with:
-          go-version: '1.24.2'
-
-      - name: Install golint
-        run: go install golang.org/x/lint/golint@latest
+          go-version: '1.25'
 
       - name: Build
         run: go build ./...

.github/workflows/docker.yaml

@@ -21,7 +21,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
 

.github/workflows/release.yaml

@@ -32,7 +32,7 @@ jobs:
 
       - uses: actions/setup-go@v4
         with:
-          go-version: "1.24.2"
+          go-version: "1.25"
 
       - name: Build
         env: