Migrate grc blocks from xml to yaml

Convert the blocks using cmdline_converter.py script from
https://gist.githubusercontent.com/haakov/4228ff6a14486641add538483093e86b/raw/c861a840e31182ace2e74f5425e356cb4f8b183a/cmdline_converter.py

Change-Id: Iee5c611a2e100bd2fdf487611a867dc937d8c292
diff --git a/grc/decryption/CMakeLists.txt b/grc/decryption/CMakeLists.txt
index 29d86f4..e71e466 100644
--- a/grc/decryption/CMakeLists.txt
+++ b/grc/decryption/CMakeLists.txt
@@ -18,5 +18,6 @@
 # Boston, MA 02110-1301, USA.
 
 install(FILES
-    gsm_decryption.xml DESTINATION share/gnuradio/grc/blocks
+    gsm_decryption.block.yml
+    DESTINATION share/gnuradio/grc/blocks
 )