Fixes a mix up of month and days in date limit calculation

Author: maxkratz

release-to-issue-java/src/main/java/org/maxkratz/releasetoissue/ReleaseToIssue.java

@@ -173,7 +173,7 @@ private Set<GHIssue> getAllTargetIssues(final GitHub github, final String target
 
     private long convertDateToEpoch(final String date) {
         checkNotNull(date);
-        SimpleDateFormat df = new SimpleDateFormat("yyyy-dd-MM");
+        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");
         try {
             final Date d = df.parse(date);
             checkNotNull(d);