build(deps): Bump actions/setup-go from 5 to 6

Bumps [actions/setup-go](https://github.com/actions/setup-go) from 5 to 6.
- [Release notes](https://github.com/actions/setup-go/releases)
- [Commits](actions/setup-go@v5...v6)

---
updated-dependencies:
- dependency-name: actions/setup-go
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -15,7 +15,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Set up Go
-        uses: actions/setup-go@v5
+        uses: actions/setup-go@v6
         with:
           go-version-file: go.mod
       - name: Cache Go Build

.github/workflows/policy-promote.yml

@@ -21,7 +21,7 @@ jobs:
       - name: Ensure bundle exists
         run: |
           test -f dist/policy-bundle.zip || echo "No bundle from previous job; rebuilding" && true
-      - uses: actions/setup-go@v5
+      - uses: actions/setup-go@v6
         with:
           go-version: '1.24'
       - name: Rebuild bundle if missing and extract digest

.github/workflows/policy.yml

@@ -16,7 +16,7 @@ jobs:
       contents: read
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-go@v5
+      - uses: actions/setup-go@v6
         with:
           go-version: '1.24'
       - name: Install opa and conftest

.github/workflows/security.yml

@@ -19,7 +19,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-go@v5
+      - uses: actions/setup-go@v6
         with:
           go-version-file: go.mod
       - name: Govulncheck

.github/workflows/supply-chain.yml

@@ -23,7 +23,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Set up Go
-        uses: actions/setup-go@v5
+        uses: actions/setup-go@v6
         with:
           go-version-file: go.mod
 
@@ -184,7 +184,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Setup Go
-        uses: actions/setup-go@v5
+        uses: actions/setup-go@v6
         with:
           go-version: '1.22'
 
@@ -208,7 +208,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Setup Go
-        uses: actions/setup-go@v5
+        uses: actions/setup-go@v6
         with:
           go-version: '1.22'