[ci][python] update pypy download link

tests/runci/targets/Python.hx

@@ -21,10 +21,10 @@ class Python {
 				if (commandSucceed(pypy, ["-V"])) {
 					infoMsg('pypy3 has already been installed.');
 				} else {
-					var pypyVersion = "pypy3.6-v7.3.0-linux64";
+					var pypyVersion = "pypy3.6-v7.3.1-linux64";
 					var file = '${pypyVersion}.tar.bz2';
 					if(!FileSystem.exists(file)) {
-						runCommand("wget", ["-nv", 'https://bitbucket.org/pypy/pypy/downloads/$file'], true);
+						runCommand("wget", ["-nv", 'https://downloads.python.org/pypy/$file'], true);
 					}
 					runCommand("tar", ["-xf", file]);
 					pypy = FileSystem.fullPath('${pypyVersion}/bin/pypy3');