Fix CI check.

Author: cqc-alec

.github/workflows/build-test

@@ -60,7 +60,7 @@ cd ${GITHUB_WORKSPACE}/tests
 python -m pip install --pre -r test-requirements.txt
 
 # update the pytket version to the lastest (pre) release
-python -m pip install --upgrade --pre pytket~=1.0
+python -m pip install --upgrade --pre pytket~=2.0
 
 # install the latest compatible pytket-qir version