Bug 22558: Don't update OS X 10.7.x and 10.8.x users to Tor Browser 7.0

"10.9" was the wrong `minSupportedOSVersion` for preventing OS X 10.7.x
and 10.8.x users from getting updated to Tor Browser 7. That it worked
for OS X 10.6.x was only by chance according to the release history table
(https://en.wikipedia.org/wiki/Darwin_(operating_system)#Release_history).

We fix that by choosing "13.0.0" (for OS X 10.9 as minimum).

tools/update-responses/config.yml

@@ -50,6 +50,6 @@ versions:
         win32:
             minSupportedInstructionSet: SSE2
         osx32:
-            minSupportedOSVersion: 10.9
+            minSupportedOSVersion: 13.0.0
         osx64:
-            minSupportedOSVersion: 10.9
+            minSupportedOSVersion: 13.0.0