Update dependency icalendar to v6.3.1 (#49)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

pyproject.toml

@@ -46,7 +46,7 @@ classifiers = [
 ]
 
 dependencies = [
-    "icalendar==6.3.0",
+    "icalendar==6.3.1",
     "recurring-ical-events==3.7.0",
     "click==8.1.8",
     "x-wr-timezone==2.0.1",