ci: build with Go 1.26 to match go.mod

The go.mod file requires Go 1.26.0. The release job runs Go 1.25 with
GOTOOLCHAIN=local, so it fails before it runs any test. The lint and
security jobs use the same pin. This change sets all three to 1.26.

.github/workflows/lint.yaml

@@ -30,7 +30,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v5
         with:
-          go-version: '1.25'
+          go-version: '1.26'
           cache: true
 
       - name: Run golangci-lint

.github/workflows/release.yaml

@@ -18,7 +18,7 @@ jobs:
   release:
     uses: lukaszraczylo/shared-actions/.github/workflows/go-release-cgo.yaml@main
     with:
-      go-version: "1.25"
+      go-version: "1.26"
       rolling-release-tag: "v1"
       platforms: >-
         [

.github/workflows/security.yaml

@@ -31,7 +31,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v5
         with:
-          go-version: '1.25'
+          go-version: '1.26'
           cache: true
 
       - name: Install govulncheck