build: move optional-dependencies to dependency-groups

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: FBumann

.readthedocs.yaml

@@ -15,4 +15,4 @@ build:
     create_environment:
       - uv venv "${READTHEDOCS_VIRTUALENV_PATH}"
     install:
-      - UV_PROJECT_ENVIRONMENT="${READTHEDOCS_VIRTUALENV_PATH}" uv sync --frozen --extra docs
+      - UV_PROJECT_ENVIRONMENT="${READTHEDOCS_VIRTUALENV_PATH}" uv sync --frozen --group docs

pyproject.toml

@@ -30,15 +30,7 @@ Homepage = "https://github.com/FBumann/xarray_plotly"
 Documentation = "https://fbumann.github.io/xarray_plotly"
 Repository = "https://github.com/FBumann/xarray_plotly"
 
-[project.optional-dependencies]
-dev = [
-    "pytest==9.0.2",
-    "pytest-cov==7.0.0",
-    "mypy==1.19.1",
-    "ruff==0.15.7",
-    "pre-commit==4.5.1",
-    "nbstripout==0.9.1",
-]
+[dependency-groups]
 docs = [
     "mkdocs==1.6.1",
     "mkdocs-material==9.7.6",
@@ -47,6 +39,15 @@ docs = [
     "mkdocs-plotly-plugin==0.1.3",
     "jupyter==1.1.1",
 ]
+dev = [
+    {include-group = "docs"},
+    "pytest==9.0.2",
+    "pytest-cov==7.0.0",
+    "mypy==1.19.1",
+    "ruff==0.15.7",
+    "pre-commit==4.5.1",
+    "nbstripout==0.9.1",
+]
 
 [project.entry-points."xarray.backends"]
 # Entry point for xarray to auto-register the accessor (xarray >= 2024.01)