Do not source triqsvars.sh in github actions build

Author: Wentzell

.github/workflows/build.yml

@@ -66,7 +66,6 @@ jobs:
         CXX: ${{ matrix.cxx }}
         LIBRARY_PATH: /usr/local/opt/llvm/lib
       run: |
-        source $HOME/install/share/triqs/triqsvars.sh
         mkdir build && cmake -B build
         cmake --build build -j2