[MNT] update GH CI action versions (#684)

In this pull request we update some of the actions used by GitHub
workflows. Those updates where made by renovate in the first place. I
highly recommend renovate. We also remove one of the two lines trying to
establish a dependency on plotly.

Author: tschm

.github/workflows/main.yml

@@ -18,17 +18,17 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - uses: actions/setup-python@v6
         with:
-          python-version: '3.13'
+          python-version: '3.14'
 
       - name: install pre-commit
         run: python3 -m pip install pre-commit
 
       - name: Checkout code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
 
@@ -63,7 +63,7 @@ jobs:
       fail-fast: false  # to not fail all combinations if just one fails
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Install uv
         uses: astral-sh/setup-uv@v7
@@ -104,7 +104,7 @@ jobs:
       fail-fast: false  # to not fail all combinations if just one fails
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Install uv
         uses: astral-sh/setup-uv@v7
@@ -144,7 +144,7 @@ jobs:
         python-version: ["3.12"]
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Install uv
         uses: astral-sh/setup-uv@v7
@@ -191,7 +191,7 @@ jobs:
       fail-fast: false
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Install uv
       uses: astral-sh/setup-uv@v7

.github/workflows/release.yml

@@ -48,7 +48,7 @@ jobs:
           python -m build --wheel --sdist --outdir wheelhouse
 
       - name: Store wheels
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v5
         with:
           name: wheels
           path: wheelhouse/*
@@ -102,7 +102,7 @@ jobs:
       id-token: write
 
     steps:
-      - uses: actions/download-artifact@v5
+      - uses: actions/download-artifact@v6
         with:
           name: wheels
           path: wheelhouse

pyproject.toml

@@ -53,7 +53,6 @@ dependencies = [
 #
 all_extras = [
     "matplotlib>=3.2.0",
-    "plotly>=5.0.0,<6",
     "ecos>=2.0.14,<2.1",
     "plotly>=5.0.0,<7",
     "cvxopt; python_version < '3.14'",