Add .gitattributes to exclude some files from production environments

Author: williamdes

.gitattributes

@@ -0,0 +1,11 @@
+/.github export-ignore
+/.php_cs export-ignore
+/.gitbook.yaml export-ignore
+/.styleci.yml export-ignore
+/.gitattributes export-ignore
+/.scrutinizer.yml export-ignore
+/docs export-ignore
+/.codeclimate.yml export-ignore
+
+# phpunit.xml.dist and tests are not excluded so tests can be run
+# this is usefull if this package ends up one day in Debian