Ignore default Recordings folder created by Unity Recorder package

Unity.gitignore

@@ -14,6 +14,9 @@
 # They also could contain extremely sensitive data
 /[Mm]emoryCaptures/
 
+# Recordings can get excessive in size
+/[Rr]ecordings/
+
 # Asset meta data should only be ignored when the corresponding asset is also ignored
 !/[Aa]ssets/**/*.meta