Remove use of requirements.txt from CI

.github/workflows/test.yml

@@ -141,10 +141,10 @@ jobs:
       - name: Install dependencies
         shell: bash -l {0}
         run: |
-          mamba install --yes -q "python~=${PYTHON_VERSION}=*_cpython" mkl numpy scipy pip mkl-service graphviz cython libgpuarray pygpu
+          mamba install --yes -q "python~=${PYTHON_VERSION}=*_cpython" mkl numpy scipy pip mkl-service graphviz cython pytest coverage pytest-cov sympy
           if [[ $INSTALL_NUMBA == "1" ]]; then mamba install --yes -q -c conda-forge "python~=${PYTHON_VERSION}=*_cpython" "numba>=0.55" numba-scipy; fi
           mamba install --yes -q -c conda-forge "python~=${PYTHON_VERSION}=*_cpython" jax jaxlib
-          pip install -q -r requirements.txt
+          pip install -e ./
           mamba list && pip freeze
           python -c 'import aesara; print(aesara.config.__str__(print_doc=False))'
           python -c 'import aesara; assert(aesara.config.blas__ldflags != "")'