Trac #33983: sage_setup: Add missing dependency

This is blocking the creation of sdists for PyPI

https://github.com/sagemath/sage/runs/6849918030?check_suite_focus=true
{{{
 File "/home/runner/work/sage/sage/local/var/lib/sage/venv-
python3.8/lib/python3.8/site-
packages/sage_setup/autogen/interpreters/utils.py", line 19, in <module>
    from jinja2 import Environment
ModuleNotFoundError: No module named 'jinja2'
}}}

URL: https://trac.sagemath.org/33983
Reported by: mkoeppe
Ticket author(s): Matthias Koeppe
Reviewer(s): François Bissey

build/pkgs/sage_setup/dependencies

@@ -1,4 +1,4 @@
-$(PYTHON) cython pkgconfig $(SAGE_ROOT)/pkgs/sage-setup/sage_setup/autogen/interpreters/specs/*.py $(SAGE_ROOT)/pkgs/sage-setup/sage_setup/command/*.py | $(PYTHON_TOOLCHAIN)
+$(PYTHON) cython pkgconfig jinja2 $(SAGE_ROOT)/pkgs/sage-setup/sage_setup/autogen/interpreters/specs/*.py $(SAGE_ROOT)/pkgs/sage-setup/sage_setup/command/*.py | $(PYTHON_TOOLCHAIN)
 
 ----------
 All lines of this file are ignored except the first.

pkgs/sage-setup/requirements.txt

@@ -1,2 +1,3 @@
 Cython
 pkgconfig
+jinja2

pkgs/sage-setup/setup.cfg

@@ -35,3 +35,4 @@ python_requires = >=3.8, <3.11
 
 install_requires =
     pkgconfig
+    jinja2