changing Travis run from pypy-3.5.1 to pypy3.5 per https://travis-ci.community/t/confusing-pypy-versions/2505

Author: mattsb42-aws

.travis.yml

@@ -99,16 +99,16 @@ matrix:
       env: TOXENV=pypy-pycrypto-norsa
     - python: pypy-5.3.1
       env: TOXENV=pypy-compatibility
-    # PyPy 5.7.1
-    - python: pypy-5.7.1
+    # PyPy 3.5 (5.10.1?)
+    - python: pypy3.5
       env: TOXENV=pypy-base
-    - python: pypy-5.7.1
+    - python: pypy3.5
       env: TOXENV=pypy-cryptography-only
-    - python: pypy-5.7.1
+    - python: pypy3.5
       env: TOXENV=pypy-pycryptodome-norsa
-    - python: pypy-5.7.1
+    - python: pypy3.5
       env: TOXENV=pypy-pycrypto-norsa
-    - python: pypy-5.7.1
+    - python: pypy3.5
       env: TOXENV=pypy-compatibility
 # matrix:
 #   include: