Update .gitattributes

Author: Dillon-Brown

.gitattributes

@@ -1,2 +1,13 @@
-# Ignore tests
-/tests export-ignore
+# Files to exclude when creating archive
+/tests export-ignore
+/.github export-ignore
+/.gitmodules export-ignore
+/.gitignore export-ignore
+/.php_cs export-ignore
+/.travis.yml export-ignore
+/.phpstan-src.neon export-ignore
+/.phpstan-tests.neon export-ignore
+/phpunit-integration.xml export-ignore
+/phpunit.xml export-ignore
+/ruleset.xml export-ignore
+/travis export-ignore