Add support for detecting Python from Pipenv files (#221)

Added the ability to enable the Python module based on the existence of the a `Pipfile`.

src/modules/python.rs

@@ -15,10 +15,16 @@ use super::{Context, Module};
 ///     - Current directory contains a `requirements.txt` file
 ///     - Current directory contains a `pyproject.toml` file
 ///     - Current directory contains a file with the `.py` extension
+///     - Current directory contains a `Pipfile` file
 pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
     let is_py_project = context
         .new_scan_dir()
-        .set_files(&["requirements.txt", ".python-version", "pyproject.toml"])
+        .set_files(&[
+            "requirements.txt",
+            ".python-version",
+            "pyproject.toml",
+            "Pipfile",
+        ])
         .set_extensions(&["py"])
         .scan();