feat: add Python Functions entries to the template .gitignore (#542)

Python support for Salesforce Functions is currently in beta.

When working on a Python project, it's typical to install the project's
dependencies inside a Python "virtual environment". This environment
is typically placed inside the project directory, with a directory name of
`.venv` or `venv`. This environment is machine-specific, so must not
be committed to source control.

In addition, when Python files are run, the Python interpreter writes the
generated bytecode to disk, as a performance improvement for subsequent
invocations. This bytecode is stored under `__pycache__` directories alongside
the source code, and is environment-specific so similarly should not be committed
to source control.

Currently the beta docs for Python Functions have the user manually edit their
project's `.gitignore`, however this adds friction and a potential source of
mistakes, so we should add these entries to the template directly.

GUS-W-12198175.

Co-authored-by: Ed Morley <[email protected]>

src/templates/project/gitignore

@@ -37,4 +37,9 @@ ehthumbs.db
 $RECYCLE.BIN/
 
 # Local environment variables
-.env
+.env
+
+# Python Salesforce Functions
+**/__pycache__/
+**/.venv/
+**/venv/