fix: build in PyPy 3.6, remove 3.5 builds from CI

Author: standy66

.travis.yml

@@ -10,12 +10,7 @@ stages:
     if: tag IS present AND type != pull_request
 env:
   # We run pypy tests first because they run the slowest
-  - PYTHON_IMAGE="pypy:3.5" PURERPC_BACKEND="asyncio"
-  # - PYTHON_IMAGE="pypy:3.5" PURERPC_BACKEND="uvloop"  # uvloop is not supported on PyPy for now
-  - PYTHON_IMAGE="pypy:3.5" PURERPC_BACKEND="curio"
-  - PYTHON_IMAGE="pypy:3.5" PURERPC_BACKEND="trio"
   - PYTHON_IMAGE="pypy:3.6" PURERPC_BACKEND="asyncio"
-  # - PYTHON_IMAGE="pypy:3.6" PURERPC_BACKEND="asyncio"  # uvloop is not supported on PyPy for now
   - PYTHON_IMAGE="pypy:3.6" PURERPC_BACKEND="curio"
   - PYTHON_IMAGE="pypy:3.6" PURERPC_BACKEND="trio"
   - PYTHON_IMAGE="python:3.5" PURERPC_BACKEND="asyncio"

setup.py

@@ -75,8 +75,8 @@ def main():
         setup_requires=["pytest-runner"],
         tests_require=[
             "pytest",
-            "grpcio",
-            "grpcio_tools",
+            "grpcio==1.25.0",           # fix version for PyPy
+            "grpcio_tools==1.25.0",     # same here
             "uvloop",
             "trio>=0.11",
             "curio>=0.9",