add: opt in color log output

README.md

@@ -47,6 +47,11 @@ workflow [`step-summary`][step-summary], and Pull Request reviews (with
 
 Create a new GitHub Actions workflow in your project, e.g. at [.github/workflows/cpp-linter.yml](https://github.com/cpp-linter/cpp-linter-action/blob/main/.github/workflows/cpp-linter.yml)
 
+> [!TIP]
+> To enable color output in the workflow logs,
+> set the environment variable `CPP_LINTER_COLOR` to a
+> value of `on`, `true`, or `1`.
+
 The content of the file should be in the following format.
 
 ```yaml
@@ -56,6 +61,7 @@ The content of the file should be in the following format.
         id: linter
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          CPP_LINTER_COLOR: on # off by default
         with:
           style: 'file'  # Use .clang-format config file
           tidy-checks: '' # Use .clang-tidy config file

action.yml

@@ -270,6 +270,14 @@ runs:
         pip install -r "$GITHUB_ACTION_PATH/requirements.txt"
         clang-tools -i ${{ inputs.version }} -b
 
+        # Install color output requirements if enabled
+        case "$CPP_LINTER_COLOR" in
+            "true" | "on" | "1")
+                pip install -r "$GITHUB_ACTION_PATH/color-requirements.txt"
+                echo "FORCE_COLOR=1" >> $GITHUB_ENV
+                ;;
+        esac
+
     - name: Run cpp-linter (Unix)
       id: cpp-linter-unix
       if: runner.os == 'Linux' || runner.os == 'macOS'
@@ -309,6 +317,14 @@ runs:
         pip install -r "$env:GITHUB_ACTION_PATH/requirements.txt"
         clang-tools -i ${{ inputs.version }} -b
 
+        # Install color output requirements if enabled
+        $colorEnabled = "true","on","1"
+        if ( $colorEnabled.contains("$env:CPP_LINTER_COLOR") )
+        {
+            pip install -r "$env:GITHUB_ACTION_PATH/color-requirements.txt"
+            echo "FORCE_COLOR=1" >> $env.GITHUB_ENV
+        }
+
     - name: Run cpp-linter (Windows)
       id: cpp-linter-windows
       if: runner.os == 'Windows'

color-requirements.txt

@@ -0,0 +1 @@
+rich==13.9.2