Add cmake for GHA

Now pulling latest riak_core

.github/workflows/erlang.yml

@@ -16,6 +16,7 @@ jobs:
       image: erlang:22.3.3
 
     steps:
+    - uses: lukka/get-cmake@latest
     - uses: actions/checkout@v2
     - name: Compile
       run: ./rebar3 compile