Upgrade SymPy Version & Extend CI

• Raise SymPy upper limit to 1.12.1
• Introduce nightly tests against sympy pre-releases

.gitlab-ci.yml

@@ -2,6 +2,7 @@ stages:
   - pretest
   - test
   - nightly
+  - docs
   - deploy
 
 # --------------------------  Templates ------------------------------------------------------------------------------------
@@ -243,7 +244,8 @@ nightly-sympy:
 # -------------------- Documentation and deploy ------------------------------------------------------------------------
 
 build-documentation:
-  stage: test
+  stage: docs
+  needs: []
   extends: .every-commit
   image: i10git.cs.fau.de:5005/pycodegen/pycodegen/documentation
   before_script:
@@ -264,6 +266,7 @@ build-documentation:
 pages:
   image: i10git.cs.fau.de:5005/pycodegen/pycodegen/full
   stage: deploy
+  needs: ["build-documentation"]
   script:
     - ls -l
     - mv coverage_report html_doc