[3.x] Don't include development related files in distribution package (#50)

Author: heelc29

.gitattributes

@@ -1,5 +1,11 @@
+.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
-.gitmodules export-ignore
-.travis/ export-ignore
-.travis.yml export-ignore
+phpunit.xml.dist export-ignore
+ruleset.xml export-ignore