lint: enable custom linters from go-lint project

pkg/db/migration_test.go

@@ -39,9 +39,9 @@ func assertForeignKeysAreGood(t *testing.T, conn *sqlx.DB) {
 	t.Helper()
 
 	// FKs should be enabled and intact at all times
-	var fkEnabled bool
-	require.NoError(t, conn.Get(&fkEnabled, `pragma foreign_keys`))
-	assert.True(t, fkEnabled)
+	var isFkEnabled bool
+	require.NoError(t, conn.Get(&isFkEnabled, `pragma foreign_keys`))
+	assert.True(t, isFkEnabled)
 	assert.NoError(t, db.PragmaForeignKeyCheck(conn))
 
 	// ...and enforcement should be in effect again, not merely reported as on