perf: address perfsprint linter findings

Enable the linter, but exclude fmt.Sprintf -> concatenation, as the
former is arguably often more readable.

.golangci.yml

@@ -15,6 +15,12 @@ linters-settings:
       - name: unused-parameter
         disabled: true
 
+issues:
+  exclude:
+    # https://github.com/catenacyber/perfsprint/issues/21
+    # https://github.com/catenacyber/perfsprint/issues/23
+    - "^fmt\\.Sprintf can be replaced with string (addi|concatena)tion$"
+
 linters:
   disable-all: true
   enable:
@@ -57,6 +63,7 @@ linters:
     - nestif
     - noctx
     - nolintlint
+    - perfsprint
     - predeclared
     - reassign
     - revive

internal/lefthook/install.go

@@ -4,7 +4,7 @@ import (
 	"bufio"
 	"crypto/md5"
 	"encoding/hex"
-	"fmt"
+	"errors"
 	"io"
 	"os"
 	"path/filepath"
@@ -31,7 +31,7 @@ const (
 var (
 	lefthookChecksumRegexp = regexp.MustCompile(`(\w+)\s+(\d+)`)
 	configGlob             = glob.MustCompile("{.,}lefthook.{yml,yaml,json,toml}")
-	errNoConfig            = fmt.Errorf("no lefthook config found")
+	errNoConfig            = errors.New("no lefthook config found")
 )
 
 // Install installs the hooks from config file to the .git/hooks.

internal/log/skip_settings_test.go

@@ -1,7 +1,7 @@
 package log
 
 import (
-	"fmt"
+	"strconv"
 	"testing"
 )
 
@@ -85,7 +85,7 @@ func TestSkipSetting(t *testing.T) {
 			},
 		},
 	} {
-		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
+		t.Run(strconv.Itoa(i), func(t *testing.T) {
 			var settings SkipSettings
 
 			(&settings).ApplySettings(tt.tags, tt.settings)