Fix gosec, govet, and errorlint linter errors

Co-authored-by: Junie <junie@jetbrains.com>

internal/crypto/crypto_test.go

@@ -2,6 +2,7 @@ package crypto
 
 import (
 	"bytes"
+	"errors"
 	"testing"
 )
 
@@ -60,7 +61,7 @@ func TestDecryptWrongKey(t *testing.T) {
 
 	ciphertext, _ := Encrypt(key1, plaintext)
 	_, err := Decrypt(key2, ciphertext)
-	if err != ErrDecryptionFailed {
+	if !errors.Is(err, ErrDecryptionFailed) {
 		t.Fatalf("expected ErrDecryptionFailed, got: %v", err)
 	}
 }
@@ -68,7 +69,7 @@ func TestDecryptWrongKey(t *testing.T) {
 func TestDecryptInvalidCiphertext(t *testing.T) {
 	key, _ := GenerateKey()
 	_, err := Decrypt(key, []byte("short"))
-	if err != ErrInvalidCiphertext {
+	if !errors.Is(err, ErrInvalidCiphertext) {
 		t.Fatalf("expected ErrInvalidCiphertext, got: %v", err)
 	}
 }