[KLC-1927] bump GitHub-owned actions to Node.js 24 runtimes

Node.js 20 is deprecated on GitHub Actions runners (forced to Node 24 from
2026-06-16, removed 2026-09-16). Bump the actions still on node20 to their
latest Node 24 majors:

  actions/setup-go        v5 -> v6
  actions/cache           v4 -> v5
  actions/upload-artifact v5 -> v7
  actions/download-artifact v6 -> v8

The klever-pipe self-hosted runner is 2.334.0, above the 2.327.1 minimum
these majors require. No params used here changed across the bumps.

Author: fbsobreira

.github/actions/go-setup-action/action.yml

@@ -24,7 +24,7 @@ runs:
   using: "composite"
   steps:
     - name: Set up Golang
-      uses: actions/setup-go@v5
+      uses: actions/setup-go@v6
       with:
         go-version: ${{ inputs.go-version }}
         cache: false
@@ -38,7 +38,7 @@ runs:
     - name: Cache Go dependencies
       id: cache_vendor
       if: inputs.cache-enabled == 'true' && runner.environment == 'github-hosted'
-      uses: actions/cache@v4
+      uses: actions/cache@v5
       env:
         cache-name: go-cache-vendor
       with:

.github/workflows/go-setup-lint.yaml

@@ -71,7 +71,7 @@ jobs:
           golangci-lint run --output.checkstyle.path=golangci-report.xml || true
 
       - name: Upload lint results
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v7
         with:
           name: lint-results
           path: golangci-report.xml

.github/workflows/pr-qa-sec.yaml

@@ -83,7 +83,7 @@ jobs:
 
       - name: Upload test results
         if: always()
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v7
         with:
           name: test-artifacts
           path: |
@@ -110,12 +110,12 @@ jobs:
           fetch-depth: 0
 
       - name: Download lint results
-        uses: actions/download-artifact@v6
+        uses: actions/download-artifact@v8
         with:
           name: lint-results
 
       - name: Download test results
-        uses: actions/download-artifact@v6
+        uses: actions/download-artifact@v8
         with:
           name: test-artifacts
 

.github/workflows/push.yaml

@@ -36,7 +36,7 @@ jobs:
           make build-validator
           
       - name: Save artifacts
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v7
         with:
           name: build
           path: |