chore: updated CHANGELOG

Author: gnikit

CHANGELOG.md

@@ -29,6 +29,8 @@
 
 ### Fixed
 
+- Fixed preprocessor bug with `if` and `elif` conditionals
+  ([#322](https://github.com/fortran-lang/fortls/issues/322))
 - Fixed bug where type fields or methods were not detected if spaces were
   used around `%`
   ([#286](https://github.com/fortran-lang/fortls/issues/286))