Bump minimum Rust version to 1.36 (required by latest 'rand').

Author: mbrubeck

.github/workflows/tests.yaml

@@ -10,7 +10,7 @@ jobs:
       matrix:
         rust:
           - stable
-          - 1.34.0
+          - 1.36.0
     steps:
       - name: Checkout
         uses: actions/checkout@v2