Update tools

Author: sebastianbergmann

.phive/phars.xml

@@ -6,5 +6,5 @@
   <phar name="phploc" version="^4.0" installed="4.0.1" location="./tools/phploc" copy="true"/>
   <phar name="psalm" version="^4.0" installed="4.10.0" location="./tools/psalm" copy="true"/>
   <phar name="humbug/php-scoper" version="^0.15.0" installed="0.15.0" location="./tools/php-scoper" copy="true"/>
-  <phar name="composer" version="^2.0.3" installed="2.1.6" location="./tools/composer" copy="true"/>
+  <phar name="composer" version="^2.0.3" installed="2.1.8" location="./tools/composer" copy="true"/>
 </phive>