Refactor Python version and badge update script

Updated Python version extraction and badge update logic in README.md.

Author: hschryver

.github/workflows/tag_and_publish.yml

@@ -25,10 +25,18 @@ jobs:
         python -m pip install -e . --group dev --no-cache-dir
     - name: Get Python version and Update README.md
       run: |
-        python_version=$(grep "requires-python" pyproject.toml | grep -o ">=[^\"]*")
-        python_badge=$(grep '^\!\[Python\]' README.md | sed -n 's/.*\(python-[^)]*\).*/\1/p')
-        new_python_badge="python-$python_version-blue?logo=python"
-        sed -i "s/$python_badge/$new_python_badge/g" README.md
+        set -euo pipefail
+        python_version=$(grep -E '^\s*requires-python\s*=' pyproject.toml | grep -oE '>=([^"]+)' | head -n1)
+        python_badge=$(grep -E '^\!\[Python\]' README.md | sed -n 's/.*\(python-[^)]*\).*/\1/p' | head -n1 || true)
+        if [[ -z "${python_badge}" ]]; then
+          echo "Python badge not found in README.md (expected a line starting with '![Python]' containing 'python-...'). Skipping."
+          exit 0
+        fi
+        new_python_badge="python-${python_version}-blue?logo=python"
+        # Escape for sed replacement (handles '/', '&', etc.)
+        esc_old=$(printf '%s' "$python_badge" | sed 's/[\/&]/\\&/g')
+        esc_new=$(printf '%s' "$new_python_badge" | sed 's/[\/&]/\\&/g')
+        sed -i "s/${esc_old}/${esc_new}/g" README.md
     - name: Get interrogate values and Update README.md
       run: |
         interrogate_val=$(interrogate . | grep -o 'actual: [0-9]*\.[0-9]*' | awk '{print $2}')