Allow Sparkle release notes to use JavaScript so videos work

Currently, it's hard to embed video in the release notes shown to
Sparkle, because by default it disables JavaScript, which video tags
need in order to work properly for the WebKit embedded browser. Turn it
on, so that we can show video instead of animated GIF's in the future
for release notes.

I don't think there should be any serious security issues after thinking
about it. The browser is sandboxed and we are serving this through https
anyway.

Author: ychin

src/MacVim/Info.plist

@@ -1309,6 +1309,8 @@
 			</dict>
 		</dict>
 	</array>
+	<key>SUEnableJavaScript</key>
+	<string>YES</string>
 	<key>SUFeedURL</key>
 	<string>https://macvim.org/appcast/latest.xml</string>
 	<key>SUPublicEDKey</key>