Add phpstan-baseline.neon and remove obsolete entries from .gitattributes

Author: richard67

.gitattributes

@@ -1,12 +1,10 @@
 .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
 phpstan.neon export-ignore
+phpstan-baseline.neon export-ignore
 phpunit.xml.dist export-ignore
 ruleset.xml export-ignore