Added make infection command to run it locally

Author: staabm

.gitignore

@@ -3,6 +3,8 @@
 /compiler/vendor
 /conf/config.local.yml
 /build-cs
+/infection.json5
+/build-infection
 /vendor
 /.idea/*
 !.idea/icon.png

Makefile

@@ -165,3 +165,12 @@ name-collision:
 
 composer-dependency-analyser:
 	php vendor/bin/composer-dependency-analyser --config build/composer-dependency-analyser.php
+
+.PHONY: infection
+infection:
+	git clone https://github.com/phpstan/build-infection.git || true
+	git -C build-infection fetch origin && git -C build-infection reset --hard origin/1.x
+	composer install --working-dir build-infection --no-interaction --no-progress
+	php build-infection/bin/infection-config.php --source-directory='build/PHPStan/Build'> infection.json5
+	php vendor/bin/infection --ignore-msi-with-no-mutations --logger-text=php://stdout
+	rm infection.json5