Ignore side-effect rule in phpcs for Decoder

.phpcs-ruleset.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0"?>
+<ruleset name="APSR2">
+  <description>Adjusted PSR2</description>
+  <rule ref="PSR2" />
+  <rule ref="PSR1.Files.SideEffects">
+     <exclude-pattern>Decoder.php</exclude-pattern>
+  </rule>
+ </ruleset>

.travis-test.sh

@@ -18,5 +18,5 @@ fi
 
 if [ $RUN_LINTER ]; then
     vendor/bin/php-cs-fixer fix --verbose --diff --dry-run --config=.php_cs
-    vendor/bin/phpcs --standard=PSR2 src/
+    vendor/bin/phpcs --standard=.phpcs-ruleset.xml src/
 fi

src/MaxMind/Db/Reader/Decoder.php

@@ -2,6 +2,7 @@
 
 namespace MaxMind\Db\Reader;
 
+// @codingStandardsIgnoreLine
 \define(__NAMESPACE__ . '\_MM_MAX_INT_BYTES', log(PHP_INT_MAX, 2) / 8);
 
 class Decoder