Update and rename pdf.yar to PDF.yar

Malicious_Documents/pdf.yar → Malicious_Documents/PDF.yar

+/*
+    This Yara ruleset is under the GNU-GPLv2 license (http://www.gnu.org/licenses/gpl-2.0.html) and open to any user or organization, as    long as you use it under this license.
+
+*/
+
 rule malicious_author : PDF
 {
 	meta:
@@ -468,4 +473,4 @@ rule XDP_embedded_PDF : PDF
 
 	condition:
 		all of ($s*) and 1 of ($header*)
-}
\ No newline at end of file
+}