Add tox as a type=optional, source=pip package

[mkoeppe]

Follow-up to #29813, which did the same for pytest.

Depends on #29813

CC: @dimpase @jhpalmieri @kiwifb

Component: packages: optional

Author: Matthias Koeppe

Branch/Commit: 1c2415e

Reviewer: Dima Pasechnik

Issue created by migration from https://trac.sagemath.org/ticket/29909

[mkoeppe]

Changed dependencies from #29345 to #29813

[mkoeppe]

Branch: u/mkoeppe/add_tox_as_a_type_optional__source_pip_package

[mkoeppe]

Commit: 1c2415e

[mkoeppe]

New commits:

04b4c67	build/pkgs/pytest: New
55babfa	src/bin/sage [-i]: Set SAGE_CHECK here so that Makefile dependencies can depend on it
bedc7ae	build/make/Makefile.in: Allow pip packages as dependencies
1c2415e	build/pkgs/tox: New

[mkoeppe]

Author: Matthias Koeppe

[mkoeppe]

Description changed:

--- 
+++ 
@@ -1,2 +1,2 @@
-Similar to #29813 for `pytest`.
+Follow-up to #29813, which did the same for `pytest`.
 

[dimpase]

comment:5

lgtm

[dimpase]

Reviewer: Dima Pasechnik

[mkoeppe]

comment:6

Thanks!

[vbraun]

Changed branch from u/mkoeppe/add_tox_as_a_type_optional__source_pip_package to 1c2415e