Fix Makefile by changing the following prerequisite name: .venv -> venv

[anmyachev]

Closes #98

Before this change, the prerequisite was not executed correctly (at least for GNU Make 4.3).

[anmyachev]

To avoid recursion.

[stinodego]

This is not valid. The folder is called .venv.

[anmyachev]

This is not valid. The folder is called .venv.

@stinodego Previous approach is more error-prone, since if an error occurs during the process of building the environment, then it will be difficult to understand what happened later.

Prerequisite doesn't have to be a file name, right? Locally, with my changes, the output is something like this:

make run-pandas
python3 -m venv .venv
make install-deps
make[1]: Entering directory '/home/anatoly/tpch'
.venv/bin/python -m pip install --upgrade uv
Requirement already satisfied: uv in ./.venv/lib/python3.10/site-packages (0.1.28)
.venv/bin/uv pip install -r requirements.txt
Audited 39 packages in 6ms
.venv/bin/uv pip install -r requirements-dev.txt
Audited 7 packages in 1ms
make[1]: Leaving directory '/home/anatoly/tpch'
.venv/bin/python -m queries.pandas.executor

It’s still fast, even if it checks not for the presence of a folder, but for installed dependencies in the environment.

[anmyachev]

@stinodego one more thought. In the current implementation, two calls in a row will not work (for example, make tables & make run-pandas), since with the second call the folder (.venv) will already be created and the virtual environment will not be activated.

[stinodego]

Prerequisite doesn't have to be a file name, right?

It does, that is the whole idea of a Makefile.

I'd like to keep the current structure, at least for now.