build: Add extra files to .gitattributes

Author: sstok

.gitattributes

@@ -1,15 +1,16 @@
 # Always use LF
 core.autocrlf=lf
 
+/doc export-ignore
+/tests export-ignore
 .editorconfig export-ignore
 .gitattributes export-ignore
 .gitignore export-ignore
 .travis.yml export-ignore
 CODE_OF_CONDUCT.md export-ignore
 .github export-ignore
 phpunit.xml.dist export-ignore
-infection.json.dist export-ignore
 phpcs.xml.dist export-ignore
 phpstan.neon export-ignore
 psalm.xml export-ignore
-psalm-baseline.xml export-ignore
+Makefile export-ignore