Use pyproject.toml as Python version source

All execution, development and validation for the project is performed using a specific version of Python.

Poetry is used for Python package dependencies management. Poetry installs dependencies into a virtual environment. For
this reason, the Poetry configuration includes a Python version number, which must match the correct version of Python
for the project. This configuration is stored in the `pyproject.toml` file.

Python is installed in the GitHub Actions runner environments using the actions/setup-python action, which also must be
configured to install the correct version of Python. Previously a the version number for use by the actions/setup-python
action was defined in the `.python-version` file. This allowed the Python version for use by the
arduino/compile-sketches action's execution and all the workflows that make up its infrastructure to be configured from
a single source. However, Poetry does not support the `.python-version` file so we were stuck with two copies of the
Python version information, which must be kept in sync.

Fortunately, support for using `pyproject.toml` as the version file for the actions/setup-python action was recently
added. This means it is now possible for all components of the project infrastructure to get the Python version from a
single source.

.github/workflows/check-python-task.yml

@@ -11,7 +11,6 @@ on:
       - "**/poetry.lock"
       - "**/pyproject.toml"
       - "**/setup.cfg"
-      - ".python-version"
       - "Taskfile.ya?ml"
       - "**/tox.ini"
       - "**.py"
@@ -22,7 +21,6 @@ on:
       - "**/poetry.lock"
       - "**/pyproject.toml"
       - "**/setup.cfg"
-      - ".python-version"
       - "Taskfile.ya?ml"
       - "**/tox.ini"
       - "**.py"
@@ -71,7 +69,7 @@ jobs:
       - name: Install Python
         uses: actions/setup-python@v5
         with:
-          python-version-file: .python-version
+          python-version-file: pyproject.toml
 
       - name: Install Poetry
         run: |
@@ -105,7 +103,7 @@ jobs:
       - name: Install Python
         uses: actions/setup-python@v5
         with:
-          python-version-file: .python-version
+          python-version-file: pyproject.toml
 
       - name: Install Poetry
         run: |

.github/workflows/check-yaml-task.yml

@@ -6,7 +6,6 @@ on:
   create:
   push:
     paths:
-      - ".python-version"
       - ".yamllint*"
       - "poetry.lock"
       - "pyproject.toml"
@@ -23,7 +22,6 @@ on:
       - "**.syntax"
   pull_request:
     paths:
-      - ".python-version"
       - ".yamllint*"
       - "poetry.lock"
       - "pyproject.toml"
@@ -99,7 +97,7 @@ jobs:
       - name: Install Python
         uses: actions/setup-python@v5
         with:
-          python-version-file: .python-version
+          python-version-file: pyproject.toml
 
       - name: Install Poetry
         run: |

.github/workflows/spell-check-task.yml

@@ -51,7 +51,7 @@ jobs:
       - name: Install Python
         uses: actions/setup-python@v5
         with:
-          python-version-file: .python-version
+          python-version-file: pyproject.toml
 
       - name: Install Poetry
         run: |

.github/workflows/test-integration.yml

@@ -7,7 +7,6 @@ on:
     paths:
       - ".github/workflows/test-integration.yml"
       - ".github/workflows/testdata/**"
-      - ".python-version"
       - "poetry.lock"
       - "pyproject.toml"
       - "action.yml"
@@ -17,7 +16,6 @@ on:
     paths:
       - ".github/workflows/test-integration.yml"
       - ".github/workflows/testdata/**"
-      - ".python-version"
       - "poetry.lock"
       - "pyproject.toml"
       - "action.yml"

.github/workflows/test-python-poetry-task.yml

@@ -11,7 +11,6 @@ on:
       - "dev/.?codecov.ya?ml"
       - ".?codecov.ya?ml"
       - "Taskfile.ya?ml"
-      - ".python-version"
       - "poetry.lock"
       - "pyproject.toml"
       - "compilesketches/tests/**"
@@ -24,7 +23,6 @@ on:
       - "dev/.?codecov.ya?ml"
       - ".?codecov.ya?ml"
       - "Taskfile.ya?ml"
-      - ".python-version"
       - "poetry.lock"
       - "pyproject.toml"
       - "compilesketches/tests/**"
@@ -75,7 +73,7 @@ jobs:
       - name: Install Python
         uses: actions/setup-python@v5
         with:
-          python-version-file: .python-version
+          python-version-file: pyproject.toml
 
       - name: Install Poetry
         run: |

action.yml

@@ -76,7 +76,7 @@ runs:
     - name: Install Python
       uses: actions/setup-python@v5
       with:
-        python-version-file: ${{ github.action_path }}/.python-version
+        python-version-file: ${{ github.action_path }}/pyproject.toml
 
     - name: Action setup
       shell: bash