chore: update to golangci-lint v2, fix some issues

Author: markgoddard

.golangci.yaml

@@ -1,15 +1,16 @@
+version: "2"
+
 linters:
   enable:
     - goheader
-
-linters-settings:
-  goheader:
-    values:
-      const:
-        COMPANY: Cofide Limited
-      regexp:
-        VALID_YEAR: 202[4-9]|20[3-9][0-9]|2[1-9][0-9][0-9]
-    # Require Cofide copyright and SPDX license in all source files.
-    template: |-
-      Copyright {{ VALID_YEAR }} {{ COMPANY }}.
-      SPDX-License-Identifier: Apache-2.0
+  settings:
+    goheader:
+      values:
+        const:
+          COMPANY: Cofide Limited
+        regexp:
+          VALID_YEAR: 202[4-9]|20[3-9][0-9]|2[1-9][0-9][0-9]
+      # Require Cofide copyright and SPDX license in all source files.
+      template: |-
+        Copyright {{ VALID_YEAR }} {{ COMPANY }}.
+        SPDX-License-Identifier: Apache-2.0

cmd/main.go

@@ -47,7 +47,9 @@ func main() {
 	}
 
 	// closing client before end of run so we have a clean output
-	client.Close()
+	if err := client.Close(); err != nil {
+		slog.Warn("Failed to close SPIFFE client", "error", err)
+	}
 
 	displayBundles(bundles)
 	displaySVIDs(svids, bundles)

cmd/main_test.go

@@ -23,6 +23,7 @@ import (
 	"github.com/spiffe/go-spiffe/v2/spiffeid"
 	"github.com/spiffe/go-spiffe/v2/svid/x509svid"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 const testCert = `-----BEGIN CERTIFICATE-----
@@ -463,11 +464,13 @@ func captureOutput(t *testing.T, fn func()) string {
 
 	fn()
 
-	w.Close()
+	err := w.Close()
+	require.NoError(t, err)
+
 	os.Stdout = old
 
 	var buf bytes.Buffer
-	_, err := io.Copy(&buf, r)
+	_, err = io.Copy(&buf, r)
 	if err != nil {
 		t.Fatalf("Failed to copy output: %v", err)
 	}