ci: really don't test agains 3.5

.github/workflows/ci.yml

@@ -89,12 +89,6 @@ jobs:
             backend: c
             env: { EXTRA_CFLAGS: "-DCYTHON_USE_TYPE_SPECS=1" }
             extra_hash: "-typespecs"
-          - os: ubuntu-18.04
-            python-version: 3.5
-            backend: c
-            env: { EXTRA_CFLAGS: "-DCYTHON_USE_TYPE_SPECS=1" }
-            extra_hash: "-typespecs"
-            allowed_failure: true
           # Stackless
           - os: ubuntu-18.04
             python-version: 2.7
@@ -150,10 +144,6 @@ jobs:
             python-version: 2.7
             backend: cpp
             env: { MACOSX_DEPLOYMENT_TARGET: 10.14 }
-          - os: macos-10.15
-            python-version: 3.5
-            backend: c
-            env: { MACOSX_DEPLOYMENT_TARGET: 10.14 }
           - os: macos-10.15
             python-version: 3.6
             backend: c