Doc: Changelog for 0.5.2

Author: FLHerne

docs/changelog.txt

@@ -1,3 +1,12 @@
+0.5.2 (2020-05-17)
+------------------------------------------------------------------------
+This release primarily fixes a spritelayout-related bug introduced in 0.5.1 that may affect many grfs.
+
+- Fix #140: non-advanced sprite layouts don't have flags
+- Fix: Make --cache-dir work
+- Fix #139: Don't create the cache directory if --no-cache is passed
+
+
 0.5.1 (2020-05-10)
 ------------------------------------------------------------------------
 This release fixes a number of issues reported in 0.5.0.