Add self-compiled openmpi version to PATH [run ci]

Author: spenke91

.github/workflows/tests_cmake_t8code_w_other_compilers.yml

@@ -90,8 +90,6 @@ jobs:
     #     echo OMPI_INSTALL_PATH="${OMPI_INSTALL_PATH}" >> $GITHUB_ENV
     #     ls $OMPI_INSTALL_PATH/bin
     #     echo "${OMPI_INSTALL_PATH}/bin" >> $GITHUB_PATH
-    - name: Show MPI version
-      run: mpicc --version
     - name: Export CLANG compiler flags
       run: |
         export CC=clang
@@ -102,6 +100,9 @@ jobs:
         echo CXX="$CXX" >> $GITHUB_ENV
         echo MPICC="$MPICC" >> $GITHUB_ENV
         echo MPICXX="$MPICXX" >> $GITHUB_ENV
+        echo "${OMPI_INSTALL_PATH}/bin" >> $GITHUB_PATH
+    - name: Show MPI version
+      run: mpicc --version
     - name: Show folder content
       run: |
         ls