Don't include development related files in distribution package (#127)

Author: heelc29

.gitattributes

@@ -1,9 +1,13 @@
 .github/ export-ignore
+.phan/ export-ignore
 docs/ export-ignore
 Tests/ export-ignore
 .drone.jsonnet export-ignore
 .drone.yml export-ignore
+.editorconfig export-ignore
 .gitattributes export-ignore
 .gitignore export-ignore
 .phpunit.cache export-ignore
-ruleset.xml
+phpunit.xml.dist export-ignore
+rector.php export-ignore
+ruleset.xml export-ignore