Add missing env

Author: Elijah Frederickson

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = pypy3-{mg34,mg36,mg39,mg311,mg312,mg4,mg432,mg441,mg462,mg473,mg480}
+envlist = pypy3-{mg34,mg36,mg39,mg311,mg312,mg4,mg432,mg441,mg462,mg473,mg480,mg49}
 skipsdist = True
 
 [testenv]
@@ -16,5 +16,6 @@ deps =
     mg462: pymongo>=4.6,<4.7
     mg473: pymongo>=4.7,<4.8
     mg480: pymongo>=4.8,<4.9
+    mg49: pymongo>=4.9,<5.0
 setenv =
     PYTHON_EGG_CACHE = {envdir}/python-eggs