CI: fix cuda test regex & docs build without TIGRE

Author: casperdcl

.github/workflows/README.md

@@ -73,7 +73,8 @@ The [docs](./build.yml#L124) job:
 > python -m http.server
 > ```
 >
-> Then open a browser and navigate to <http://localhost:8000/CIL/> to view the documentation.
+> Then open a browser and navigate to <http://localhost:8000/CIL/{PR_NUMBER}_merge/> to view the documentation,
+> where `{PR_NUMBER}` is the number of the PR that was built (e.g. `1234`).
 
 ## [skip.yml](./skip.yml)
 

.github/workflows/build.yml

@@ -72,7 +72,7 @@ jobs:
     - uses: actions/checkout@v4
       with: {fetch-depth: 0, submodules: recursive}
     - name: set requirements
-      run: sed -ri -e '/ python /d' -e 's/(.* numpy) .*/\1=${{ matrix.numpy-version }}/' -e 's/=cuda*//' -e '/tigre/d' scripts/cil_development.yml
+      run: sed -ri -e '/ python /d' -e 's/(.* numpy) .*/\1=${{ matrix.numpy-version }}/' -e 's/cuda*//' -e '/tigre/d' scripts/cil_development.yml
     - uses: conda-incubator/setup-miniconda@v3
       with:
         python-version: ${{ matrix.python-version }}
@@ -224,6 +224,7 @@ jobs:
     - name: install dependencies
       run: |
         mamba install -c conda-forge -yq conda-merge
+        sed -ri -e 's/cuda*//' -e '/tigre/d' ../scripts/cil_development.yml
         conda-merge ../scripts/cil_development.yml docs_environment.yml > environment.yml
         mamba env update -n test --file environment.yml
         conda list