[ci] Use hererocks activate script

Author: tobil4sk

.github/workflows/ci.yml

@@ -17,16 +17,15 @@ jobs:
         run: |
           pip install hererocks
           hererocks lua_install -r^ --${{ matrix.lua }}
-          export PATH=$PATH:$PWD/lua_install/bin
           luarocks install lua-cjson2
         env:
           MACOSX_DEPLOYMENT_TARGET: 11.0
       - name: Build lua-simdjson
         run: |
-          export PATH=$PATH:$PWD/lua_install/bin
+          source lua_install/bin/activate
           luarocks make
       - name: Run tests
         run: |
-          export PATH=$PATH:$PWD/lua_install/bin
+          source lua_install/bin/activate
           luarocks install busted
           busted --verbose